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Full text of "Printer Manual: Apple Laserwriter 12.640 PS"

Service Source 



E 




LaserWriter 12/640 PS 



■► 



Service Source 




Overview 



LaserWriter 12/640 PS 



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Overview 



About This Overview - 1 




About This 
Overview 

This overview briefly 
describes the servicing 
issues of the LaserWriter 
12/640 PS, especially 
those that distinguish it 
from previous Apple laser 
printers. 



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Overview 



General - 2 



General 




The LaserWriter 12/640 
PS is a 600 dpi, 12 ppm 
monochrome laser printer 
that is positioned as the 
workgroup laser printing 
solution for Mac OS and 
Windows users. 

It features excellent print 
quality, cross platform 
support, and state-of-the- 
art paper handling options. 

LaserWriter driver 8.4 
releases concurrently with 
this printer. 



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Overview 



Options - 3 




LW 12/640 PS Options 



Options 



There are three options that are available for the Laser- 
Writer 12/640 PS: 

• Duplexer unit 

• Face-up catch tray 

• 500-sheet feeder (accommodates either standard or 
envelope cassette) 

Each of the options can be added independently of one another 
so there are several configurations that you might 
encounter. The animation "LW12/640 PS Options" shows 
how the options go together. 



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Overview 



Paper Path - 4 




LW12/640 PS Paper Path 



Paper Path 



The printer has a basic S-shaped paper path and multi- 
purpose tray arrangement generally similar to the Laser- 
Writer 16/600 PS. 

On the exit side of the fuser assembly, however, there is a 
brand new function: the paper deflector guide. This 
solenoid-actuated guide switches paper between one of two 
paths. The inside path is the face-down delivery path that 
continues straight up to the delivery rollers and output tray. 
The outside path serves three purposes. 

• Paper feed into the optional duplexer. 

• Paper delivery to the optional face-up tray. 

• If no options are attached, the outside path will feed 
paper directly out the rear of the printer. 

Note: The "LW 12/640 PS Paper Path" animation shows 
the sequence of a duplex print job. 



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Overview 



Duplexer - 5 



Duplexer 




The most unique mechanical feature you will encounter is 
the optional duplexer unit. The term "duplex" denotes two- 
sided printing. 

The duplexer is an L-shaped feeder that cradles the 
underside and rear of the printer. When duplex printing is 
selected through software, the paper deflector guide is 
actuated and the sheet of paper diverts into the duplexer. 
There the paper is flipped and circulated back to the cassette 
feed roller in preparation for its second imaging cycle. 

The drive train in the horizontal leg of the duplexer receives 
drive directly through an idler gear in the pickup drive 
assembly in the printer. The feed roller at the entrance to 
the duplexer also receives drive from the printer, but the 
other feed rollers in the vertical leg of the duplexer are 
driven by the duplexer motor. 



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Overview 



Sheet Feeder - 6 



Sheet Feeder 




An optional 500-sheet feeder is available. As with the 
LaserWriter 16/600 PS design, the sheet feeder fits 
squarely beneath the printer (or the duplexer, if present) 
to form a dual front-loading cassette arrangement. An 
envelope cassette is available for the sheet feeder only. 

The feeder has a receptacle connector that mates with the 
printer and has its own circuit board. However, the feeder 
does not have its own motor. Instead it derives mechanical 
drive directly from the gear train above, either the pickup 
drive assembly in the printer or the intermediate gear train 
in the duplexer. There is a pickup roller and pickup 
solenoid in the sheet feeder. 



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Overview 



Face-Up Tray - 7 




Optional 
Face-Up Tray 



Face-Up Tray 



The face-up tray is an option that attaches to the rear of the 
printer (or to the rear of the duplexer, if present). 

This tray performs similarly to previous printers, except 
that output to this tray is selected through software, not by 
the setting of a lever. The presence of this tray is not sensed 
by the controller. 



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Overview 



Duplex Scan Anomalies - 8 



Feed Leading Edge 



First Pass 
(Page 2) 




Duplex Scan Anomalies 

After side one prints during a duplex job, the paper parks 
itself onto a horizontal shelf beneath the cassette. The 
duplexer motor then reverses direction. The trailing edge of 
the paper becomes the leading edge, and the paper exits the 
shelf and continues the path toward side-two printing. 

Order of Scanning 

Duplex documents stack in the face-down delivery tray in 
correct book order (with odd-numbered pages facing down). 
To achieve this, page two is imaged during the first pass and 
page one during the second pass. 

Long Edge Binding 

The reversing action of the duplexer flips the paper over 
along its short axis. If you have chosen long edge binding in 



Second Pass 
(Page 1 ) 



Leading Edge 



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-quo fa 


rritnit; 


e " Scan 



Long Edge Binding 
Scan/ Feed Directions 



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Overview 



Duplex Scan Anomalies - 9 



Feed 



the software, the I/O controller flips the imaging data 
accordingly to counteract the reversal of the paper. The net 
effect is even-numbered pages scanned in reverse. 



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Ipso I 
quof-s 
trispit 



Ipso I 
quofe 
trispit 



First Pass 
(Page 2) 



Second Pass 
(Page 4) 



Third Pass 
(Pagel) 



Fourth Pass 
(Page 3) 



Sequence of 
Double-Page Batching 



For example, page 2 of a portrait oriented job images right 
to left from the bottom up. (This anomaly does not occur 
with short edge binding). For this reason, be aware that 
some skew or image cutoff symptoms may appear to be 180 
degrees off from normally scanned pages. 

Double-Page Batching 

If there is enough buffer memory space available, the 
controller will image a print job four pages (two sheets) at 
a time. For example, the imaging order of an eight-page 
document would be pages 2, 4, 1, and 3 (with sheets one and 
two then being delivered), followed by pages 6, 8, 5, and 7 
(with sheets three and four delivered). This batching 
feature maximizes throughput speed. 



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Overview Miscellaneous - 10 

Miscellaneous 

Fuser Pressure Roller 

The fuser pressure roller provides an opposing surface to 
the fuser heater roller, the same function as in previous 
laser printers. However in the LaserWriter 12/640 PS, 
this pressure roller is seated in the chassis and is not a part 
of the fuser assembly itself. 

Power Supply Assembly 

The power supply assembly is a large multifunctional 
circuit board located in the lower section of the engine. In 
addition to the DC power supply functions that are common 
in previous engines, this assembly also houses some sensors 
and switches, as well as the high-voltage power supply and 
various other functions. 



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Overview Miscellaneous - 11 

Beam Detection 

Laser beam detection occurs outside of the laser/ scanner 
assembly, in the start-of-scan (SOS) sensor located in the 
mirror assembly. 

Two Shutters 

There are two laser shutters, one inside the laser/ scanner 
assembly and one covering the mirror assembly. Both are 
actuated with the closure of the top cover. 

Two "Exit" Sensors 

Unlike previous printers, there are two paper sensors 
downstream of the fuser assembly. The first is the fuser 
exit sensor that monitors the exiting of paper from the fuser 
assembly. The second is the delivery sensor that monitors 



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Overview Miscellaneous - 12 

paper after it passes the deflection guide in route to face- 
down delivery on top of the printer. 

One Fan 

There is only one fan in this printer. 

Support for Heavy Paper 

The LaserWriter 12/640 PS supports throughput of 50 lb. 
paper for simplex (single-sided) print jobs. You must 
print from the multipurpose tray and choose face-up 
delivery when using 50 lb paper. 

RAM Upgrade 

The LaserWriter 12/ 640 PS comes with 4 MB of RAM in the 
righthand of two SIMM slots. This amount does not allow for 



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Overview Miscellaneous - 13 

duplex printing nor does it enable PhotoGrade. Upgrades are 
required if you want either of these additional features. 

No SCSI 

There is no SCSI support in the LaserWriter 12/640 PS. 

Startup Page 

The startup page is a single-sided page with a layout similar 
to previous PostScript LaserWriter printers. The startup 
page does report the presence of a duplexer or sheet feeder 
but will not recognize the optional face-up tray. 



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Overview 



Miscellaneous - 14 




Service Test Page 

You may print a service test 
page by jumpering 
connectorj 101 on the I/O 
controller board. Conse- 
quently, unlike previous 
printers, the I/O controller 
board must be installed to 
run a service test page. 



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Overview Miscellaneous - 15 

Top Cover Closure 

The closing of the top cover initiates several more events 
than in previous printers. They are listed below and are 
described in detail in the "Principles of Operation" chapter. 

• Actuation of cover interlock 

• Opening of the laser shutter 

• Opening of the mirror assembly shutter 

• Latching of the top cover 

• Pressing of the jam release plate 

• Actuation of the toner cartridge latching mechanism 

• Actuation of the fuser idler gear 



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Service Source 




Principles of Operation 

LaserWriter 12/640 PS 



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Principles of Operation 



Print Process - 1 



Print Process 



Print Process Overview 

The print process consists of the stages shown below, during which a toner image forms on 
the drum surface, transfers and then bonds to the paper. Each sheet of paper passes through 
steps 4 to 6. During printing,the drum surface repeatedly cycles through steps 1 to 5, as 
well as cleaning stage 7. 



Charging 



Exposure 



Development 



Paper Enters 



A 



Xerographic Cycle 



Cycle repeats for the next print 



7 
Cleaning 



Paper Exits 

L 



4 
Transfer 




5 
Discharge 




6 
Fusing 






V 







1 Charging 

Places a uniform density of negative electric charge onto the drum surface. 

2 Exposure 

Scans the drum surface with a thin beam of laser light that switches on and off according to 
the video signal from the printer controller. This exposure forms an invisible electrostatic 
latent image on the drum surface. 

3 Development 

Attracts toner onto the electrostatic latent image on the drum surface, thus forming a 
visible toner image. 

4 Transfer 

Transfers the toner image from the drum surface to the paper. 

5 Discharge 

Enables the paper to come off the drum surface. 

6 Fusing 

Fixes the toner image to the paper. 

7 Cleaning 

Cleans the drum surface of any residual toner. 



Ifflj Principl 



es of Operation 



Print Process - 2 



Print Process Diagram and Paper Path 



Laser Beam 



CM Blade 




Attraction Roller 
Paper 



Transfer Roller 



Detack Saw 



Cleaning Blade 



Fuser Roller 



Pressure Roller 



Mirror Assembly Toner Cartridge 

BCR CM Blade Laser/ Scanner Assy 




Drum Detack Saw Transfer Roller Attraction Roller 



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Principles of Operation 



Print Process - 3 



Print Process Description 
1 Charging 

During this stage, the drum surface receives a uniform negative charge. 

Note: The drum surface is made of a photoconductive material and the inner part of the 
drum is made of a conductive material. This negative charge is actually placed onto the 
outside surface of the photoconductor layer. 

The charge is imparted by the bias charge roller (BCR) within the toner cartridge. The 
BCR is a conductive roller in contact with the drum surface and is supplied with a discharge 
voltage by the high-voltage power supply (HVPS). The discharge occurs through the small 
gaps between the BCR and the drum. The discharge voltage is an AC voltage with a negative 
DC voltage superposed. The negative DC voltage is about -330 V. The AC voltage varies 
within the range of about 1.6 to 2.0 kVp-p with the discharge current since the AC current 
is regulated to be constant. 

Note: Before this stage, the drum surface will have been given a uniform negative 
charge relative to the inner conductor of the drum (see "Cleaning"). 



High-Voltage 

Power Supply 

(HVPS) 



Bias Charge Roller (BCR) 




© Negative Charge 
=£= Positive Charge 



Photoconductor Layer 



Conductor Layer 



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Principles of Operation 



Print Process - 4 



2 Exposure 

During this stage, the laser beam scans across the negatively charged drum surface. 

The laser beam is emitted from the laser diode in the laser/ scanner assembly. This diode is 
stationary. Its beam reflects off the face of a rapidly rotating scanning mirror, through a 
correction lens, and outward off a stationary mirror which directs the beam onto the 
surface of the drum. 

The laser beam is modulated according to the video signal from the printer controller, 
switched on when the video signal denotes a black pixel and off when it denotes a white pixel. 

The laser beam that strikes the drum surface generates electron-hole pairs in the 
photoconductor layer, exciting electrons to the conduction band and thereby creating holes 
in the valence band. The electrons are attracted by the electric field and move toward the 
inner conductor of the drum to flow into it. The holes move toward the outside surface of the 
photoconductor layer and recombine with the negatively charged electrons at the surface to 
decrease the negative charge at the surface. The resultant less-negatively charged parts 
(parts whose potential has risen relative to the inner conductor) in the drum surface form 
an invisible electrostatic latent image. 



Laser Light 



Electron 



Recombination Decrease of 

Negative Charge 



P><P)<P) _Q 0_ 




+ + + + 



e e 



Electron-hole pair 



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Principles of Operation 



Print Process - 5 



3 Development 

During this stage, the electrostatic latent image on the drum surface attracts toner and 
forms a visible toner image. 

The LaserWriter 12/640 PS uses nonconducting magnetic toner that readily transfers to 
plain paper. The toner is supplied from the toner compartment to the attraction roller 
positioned close to the drum within the toner cartridge. Because of its slight magnetism, the 
toner is attracted to the surface of the attraction roller and is spread evenly into a very thin 
layer by the charging and metering blade (CMB). This blade is made of silicone rubber. As 
it comes into contact with the toner, the resulting friction imparts a negative charge onto 
the toner particles. 

The attraction roller is covered with a thin conductive sleeve. A development bias (DB) 
voltage is applied to the conductive sleeve from the HVPS. The DB voltage is a negative DC 
voltage with an AC voltage superposed. The DC voltage is about -250 V and the AC voltage is 
about 1.7 kVp. 

Since the attraction roller is kept at a potential of about -250 V DC relative to the 
conductor layer of the drum, the parts of the drum surface with the full negative charge 
have a lower electric potential than the attraction roller, and the parts with decreased 
negative charge have a higher electrical potential. 

Therefore, the negatively charged toner on the attraction roller is pulled only to those areas 
of the drum with the decreased negative charge (since the attracting force of the positive 
charge on the conductor layer of the drum is greater than the repelling force of the negative 
charge on the drum surface, the toner is attracted in spite of the repelling force of the 
negative charge). As the toner adheres, the negative charge of those parts increases because 
of the negative charge of the toner, lowering the electric potential and increasing the 
repelling force of those parts to decrease the resultant attracting force. 

The AC voltage agitates the toner particles on the attraction roller surface and facilitates 
toner release. The invisible electrostatic latent image on the drum surface is thus developed 
into a visible toner image. 



HVPS 



(^-Oac 



DC 



Development Bias 



Scanner 



Exposure 



eee 




Irradiated Part of 
^/the Drum Surface 



Charging 



Conductor 
Layer 



Photoconductor 
Layer 



CM Blade 



Oo 
Oo o 
O O O 



Negative Charge 
Positive Charge 
Negatively Charge Toner 
Non-Charged Toner 



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Principles of Operation 



Print Process - 6 



3 Development (cont.) 



The change of the electric potential of the drum surface while the drum 
surface passes through the charging to the development steps 



V |, 



Development Bias 
About -250 V 



Bias Charge 
About -330 V 




<L Charged 
i Exposed 
-i Developed 



Conductor Layer Drum Surface 
of the Drum 



Attraction Roller 



a: The electric potential of the parts of the drum surface struck 
by the laser beam (the areas with decreased negative charge) 
rises above the electric potential of the attraction roller. 

b: The electric potential of the parts with decreased negative charge 
lowers as the toner is attracted. 

c: The degree of inclination of the line indicates the strength 
of the force and the direction of inclination indicates the 
direction of the force exerted on the toner particles. 



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Principles of Operation 



Print Process - 7 



3 Development (cont.) 

The diagram below illustrates the change of the potential as the drum surface passes from 
the charging through the development stages:. 



1 Charging 



Drum Surface 



Voltage 



-V 



About -233V 
Bias Charge 



2 Exposure 




Electrostatic Latent 
Image (Invisible) 



♦ i i 



-v 



3 Development 




Toner Image 
(Visible) 






About -250V 
Development Bias 



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es of Operation 



Print Process - 8 



4 Transfer 

During this stage, the toner transfers from the drum to the paper. 

The bias transfer roller (BTR), referred to herein simply as the transfer roller, applies a 
positive charge to the back side of the paper as it feeds between the roller and the drum. The 
toner image transfers from the drum surface to the front side of the paper due to this 
positive charge on the back side of the paper. 

The paper is attracted by the negative charge induced in the inner conductor layer of the 
drum by the positive charge of the paper and sticks to the drum surface. 



Laser Beam 



HVPS 




Drum 



Paper 




Conductor Layer 

Photoconductor 
Layer 



© Negative Charge 

=5= Positive Charge 

• Negatively Charged Toner 



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Principles of Operation 



Print Process - 9 



5 Discharge 

During this stage, the paper comes off the drum surface. 

The detack saw applies a negative charge to the back side of the paper to neutralize the 
positive charge previously applied by the transfer roller. The force which attracts the 
paper to the drum surface disappears, and the paper releases naturally from the drum due 
to gravity. 



Laser Beam 






4 o o &2~H£§- paper 


HVPS 




^ — 

DS 


Detack Saw 


















H 














77 


V 







=S= Positive Charge 

• Negatively Charged Toner 

O Non-Charged Toner 



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Principles of Operation Print Process - 10 



6 Fusing 

During this stage, heat and pressure fix toner to the paper. 

The toner image transferred from the drum surface to the paper is easily dislodged. To fix 
the image to the paper, the paper is passed between the fuser assembly and a pressure 
roller. The fuser roller applies the heat necessary to bond toner to paper and also supplies 
rotational force to help pull the paper evenly through. The pressure roller, though neither 
heated or mechancially driven, provides the surface against which the pressure and heat can 
be evenly applied. 



Service Source 




Specifications 



LaserWriter 12/640 PS 



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Specifications Introduction - 1 



Introduction 

Specifications information for this product can be found in this chapter and also in the Spec 
Database, which you can access in one of three ways: 

— Launch it directly by double-clicking the Apple Spec Database runtime alias at the 
top level of the Main Service Source CD. 

— Select "Apple Spec Database" from the Service Source drop-down main menu. 

— Click the Acrobat toolbar icon for the database, which is near the right end of the 
toolbar with the letters "SP." 



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Specifications 



Engine - 2 



Engine 



Marking Engine 



Fuji Xerox P893 laser-xerographic 



Laser 



Type: Semiconductor laser GaAIAs 
Wavelength: 780 nm 
Output power: 5 mW 



Speed 



Simplex — 12 pages per minute maximum using A4-size paper. 

Actual speed depends on the images printed. 
Duplex — 8 pages per minute maximum using U.S. letter-size 

paper. Actual speed depends on the images printed. 



Life Expectancy 
(Printer) 



Average number of prints between failure is 1 80,000 pages. 



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Specifications 



Engine - 3 



Life Expectancy 
(Toner Cartridge) 



Life expectancy is 6,000 pages when printing text documents with 
average page coverage (5% black). An example of a 5% black 
page coverage is a page consisting of double-spaced 1 4-point 
courier type. Printing images and other graphics may impact 
toner cartridge life expectancy. 



Printing Materials 



1 6- to 28-pound laser-quality bond (60 to 90 g/m 2 ); up to 
50-pound (1 90 g/m 2 ) stock when fed manually through the 
multipurpose tray and delivered through the face-up output 
tray. Accepts most textured and colored stock. Accepts medium- 
weight photocopier transparencies and labels. Envelopes can be 
printed from the multipurpose tray or from the optional 
envelope cassette (sheet feeder only). 

The paper used should not scorch, melt, transfer material, or 
release hazardous emissions when heated to 200° C (393° F) 
for 0.1 seconds. 



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Specifications Engine - 4 



Paper Sizes and Supports U.S. letter, A4, B5, executive, and legal in the standard 

Capacity paper cassette. The paper cassette holds 250 sheets of 20- 

pound (75 g/m 2 ) paper. The multipurpose tray can hold up to 
80 sheets of standard U.S. letter paper, and other paper sizes 
from postcard up to U.S. legal. An optional 500-sheet cassette 
is available that supports letter, A4, and U.S. legal-paper 
sizes. An envelope cassette that can automatically feed up to 50 
envelopes is also available. The envelope cassette is compatible 
only with the 500-sheet feeder. 



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Specifications Engine - 5 



Dimensions Printer only 

Height 9.5 in. 24.2 cm) 



Width 15.9 in. (40.5 cm) 

Depth 16.7 in. (42.4 cm) 

Printer with optional duplex printing unit 

Height 1 1.89 in. (30.2 cm) 

Width 15.9 in. (40.5 cm) 

Depth 20.47 in. (52.0 cm) 

Printer with optional 500-sheet cassette and feeder 

Height 14.0 in. (35.6 cm) 

Width 15.9 in. (40.5 cm) 

Depth 16.7 in. (42.4 cm) 

Printer with optional duplex printing unit and 500-sheet 

cassette feeder 
Height 16.2 in. (41.1cm) 
Width 15.9 in. (40.5 cm) 
Depth 20.4 in. (52.0 cm) 



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Specifications Engine - 6 



Weight Approximately 30 lb. (14 kg) 

Voltage U.S. 

Requirements 1 03.5 to 1 26.5 VAC, 58 to 62 Hz 

Europe/Australia 
1 98 to 264 VAC, 48 to 52 Hz 



Note: The LaserWriter 1 2/640 PS printer does not contain a 
universal power supply or fuser assembly. 



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Specifications Engine - 7 



Power Consumption Energy-saving mode 

26 W 



Standby average 

1 00/1 20 V, approximately 1 25 W 
220/240 V, approximately 1 20 W 
Operating average 

I 1 0/1 20 V, approximately 390 W 
220/240 V, approximately 370 W 
Maximum power consumption 

I I 0/1 20 V, approximately 790 W, 6.8 A 
220/240 V, approximately 770 W, 3.5 A 



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Specifications 



I/O Controller - 8 



I/O Controller 



Microprocessor 

ROM 

RAM 



AMD Am29040 30-MHz RISC microprocessor 

4 MB (including 35 Type 1 fonts) 

4 MB (expandable to 64 MB) 

72-pin, 70 ns or less SIMMs are required. See "Upgrades" for 
full information about possible configurations. 



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Specifications 



I/O Controller - 9 



Ports 



LocalTalk 

Parallel 

AAUI Ethernet port with three protocols: 

EtherTalk 

Novell NetWare IPX (PSERVER or RPRINTER) 

TCP/IP (BSD Ipd) 
External Ethernet transceivers available for: 

Thin Coax (10BASE-2) 

Twisted Pair (10BASE-T) 

Thick Coax (10BASE-5) 
(All ports/protocols simultaneously active) 
Two-position communication switch 



Resolution 



600 dpi 



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Specifications I/O Controller - 10 



Grayscale Imaging Standard 

85 lines/inch dithered halftone, 101 gray levels 
106 lines/inch dithered halftone, 129 gray levels 
141 lines/inch dithered halftone, 73 gray levels 
PhotoGrade (1 2 MB of RAM required) 
85 lines/inch halftone, 201 gray levels 
106 lines/inch halftone, 257 gray levels 
141 lines/inch halftone, 145 gray levels 

Languages PostScript Level 2 (2015) 

PCL5 (LaserJet MID emulation) 



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Specifications I/O Controller - 1 1 



Fonts on Disk Sixty-four fonts are provided with the LaserWriter 1 2/640 PS, 

including such fonts as ITC Avant Garde ® , ITC Bookman ® , 
Chicago, Courier, Delphian, Garamond Condensed, Geneva, 
Helvetica ® , Helvetica Black, Helvetica Compressed, Helvetica 
Narrow, Lubalin Graph, Lucida Bright, Machine, Monaco, 
Nadianne, New Century Schoolbook, New York, Old English 
Text, Onyx, Oxford, Palatino ® , Swing, Symbol, Times ® , ITC 
Zapf Chancery ® , ITC Zapf Dingbats ® , and Zeal. 



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Specifications 



I/O Controller - 12 



Fonts in ROM 



PostScript 



The following fonts are resident in the printer ROM: 
AvantGarde Book, AvantGarde BookOblique, AvantGarde Demi, 

AvantGarde DemiOblique 
Bookman Demi, Bookman Demiltalic, Bookman Light, Bookman 

Lightltalic 
Courier, Courier Bold, Courier BoldOblique, Courier Oblique 
Helvetica, Helvetica Bold, Helvetica Bold Oblique, Helvetica 

Narrow, Helvetica Narrow Bold, Helvetica Narrow 

BoldOblique, Helvetica Narrow Oblique, Helvetica Oblique 
NewCentury Schoolbook Bold, NewCentury Schoolbook Boldltalic, 

NewCentury Schoolbook Italic, NewCentury Schoolbook Roman 
Palatino Bold, Palatino Boldltalic, Palatino Italic, Palatino Roman 
Symbol 

Times Bold, Times Bold Italic, Times Italic, Times Roman 
Zapf Chancery Mediumltalic 
Zapf Dingbats 



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Specifications I/O Controller - 1 3 



PCL The following PCL fonts are resident in the printer ROM: 

Times Roman, Time Bold, Time Italic, Times Bold Italic 
Univers Medium, Univers Medium Bold, Univers Medium Italic, 

Univers Medium Bold Italic 
Courier 1 2 pitch, 1 point Medium; Courier 1 2 pitch, 1 point 

Bold; Courier 12 pitch, 10 point Italic; Courier 10 pitch, 12 

point Medium; Courier 1 pitch, 1 2 point Bold; Courier 1 

pitch, 1 2 point Italic 
Line Printer Font 16.67 pitch, 8.5 point, Medium 



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Specifications 



Environmental Information - 1 4 



Environmental Information 



Operating 
Temperature 



50° to 90° F (10° to 32° C) 



Operating Humidity 1 5 to 80 percent RH non-condensing 



Storage (Toner 
Cartridge) 



Temperature 32° to 95° F (0° to 35° C) 
Humidity 1 5 to 85 percent RH non-condensing 



Storage (Printer) 



Temperature 32° to 1 22° F (0° to 40° C) 
Humidity 35 to 85 percent RH non-condensing 



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Specifications 



Finished Goods Accessories - 1 5 



Finished Goods Accessories 



Ethernet 



Apple Ethernet Thin Coax Transceiver M0329Z/B 
Apple Ethernet Twisted Pair Transceiver M0437Z/B 
Apple Ethernet AUI Adapter M0432LL/A 



Toner Cartridge 
Printer Options 



LaserWriter 1 2/640 PS Toner Cartridge M4683G/A 

LaserWriter 1 2/640 PS 500-Sheet Feeder M4682G/A (includes 
standard 500-sheet cassette). Envelope cassette M4680G/A is 
also available for the sheet feeder. 
LaserWriter 1 2/640 PS Face-Up Output Tray M4698G/A 
LaserWriter 12/640 PS Duplex Printing Unit M4697G/A 



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Principles of Operation 



Print Process - 11 



7 Cleaning 

During this stage, any residual toner on the drum is cleaned off to prepare for the next 
print cycle. 

The residual toner is collected in a special compartment separate from the fresh toner 
compartment. The transfer rate is more than 90%, but varies according to the percentage 
of printed pixels and the environmental conditions such as temperature and humidity. 
Residual toner cannot be re-used. 



Cleaning Blade 



Used Toner 




Toner Cartridge 



Silicone Rubber 



F^n Principles of Operation 

Paper Transportation 



Paper Transportation - 12 



Paper Path Flowchart 

The chart below shows the parts that feed paper through the LaserWriter 12/640 PS 
engine. Parts are shown in the order in which they occur during a print cycle. 



Pickup Roller 
(Optional Sheet Feeder) 



Cassette Feed 
Pickup Roller 



Manual Feed 
Pickup Roller 



Cassette Feed Roller 



t 



Duplexer 



Preregistration Feed and Pinch Rollers 



Registration Feed and Pinch Rollers 



Drum and Transfer Roller 



Fuser Roller and Pressure Roller 



Fuser Exit and Pinch Rollers 



Paper Deflector Guide 



JL. 



Duplexer and/ or 
Face-Up Delivery Tray 



Delivery Rollers 
and Pinch Rollers 



Output Tray 



m 



Principles of Operation 



Paper Transportation - 13 



Paper Path Diagram 

The cross-sectional diagram below illustrates the elements indicated in the previous chart. 
The roller diameters are listed below the diagram. 



Delivery Roller 



Drum 



Registration Pinch Roller 



Delivery 
Pinch Roller 



Fuser Roller 

Fuser Pinch Roller 
Fuser Exit Roller 

Pressure Roller 




Transfer 
Roller 



Registration 
Feed Roller 



Cassette 
Pickup Roller 



Preregistration 
Pinch Roller 

Manual Feed 
Pickup Roller 

Preregistration 
Feed Roller 

Cassette Feed 
Pinch Roller 



Cassette Feed 
Roller 



Roller 

Delivery Roller 
Drum 

Registration Pinch Roller 
Delivery Pinch Roller 
Fuser Roller 
Fuser Pinch Roller 
Fuser Exit Roller 
Pressure Roller 
Transfer Roller 
Registration Feed Roller 
Cassette Pickup Roller 
Cassette Feed Roller 
Cassete Feed Pinch Roller 
Preregistration Feed Roller 
Manual Feed Pickup Roller 
Preregistration Pinch Roller 



Diameter (inches/ mm) 



.39- 



34 in. 


8.8 mm 


18 


30.0 


39 


10.0 


43 


10.0-10.8 


89 


22.6 


31 


8.0 


53 


13.6 


90 


23.0 


63 


15.9 


56 


14.3 


79 


20.0 


55 


14.0 


79 


20.0 


55 


14.0 


55 


14.0 


63 


16.0 



\~fi?\ Principles of Operation 

Print Image Creation 



Print Image Creation - 14 



Print Image Generation 

The image data signal (VIDEO) is sent from the I/O controller board to the laser/ scanner 
assembly via the DC controller board. The video signal is passed through the DC controller 
board as received from the I/O controller without buffering or additional processing. The 
signal is converted into laser light, which is scanned onto the surface of the photosensitve 
drum as described below. As a result, an electrostatic latent image is produced on the drum 
surface. 



Mirror Assembly 



Laser/ Scanner 
Assembly 



I/O Controller 




V* 



Host Computer 
Interface Cable 



Drum 



DC Controller Board 



m 



Principles of Operation 



Print Image Creation - 15 



Laser/Scanner Assembly Structure and Operation 

The laser light source used for the LaserWriter 12/600 PS is a semiconductor laser diode 
(LD) with a rated maximum output power of 5 mW. 

The laser diode is switched on and off according to the video signal. The power of the laser 
light is monitored and controlled by the monitor circuit so that it remains constant. 

The laser light from the diode is aimed directly at a hexagonal mirror that is being rotated 
at a very high speed by the scanner motor. The six facets of the mirror reflect the laser 
beam in turn as the mirror rotates. 

The beam reflected by the hexagonal mirror passes through a correction lens and outward 
from the laser/ scanner assembly. The beam reflects downward off a stationary mirror and 
through a slit in the toner cartridge, striking the surface of the photosensitive drum. 

At the beginning of each scan, the laser beam strikes the start-of-scan (SOS) sensor. The 
on and off switch of the laser light is determined by the signal from the SOS sensor. 



Start-of-Scan (SOS) Sensor 



Stationary Mirror 



Laser Diode Board 



Hexagonal Mirror 




Correction Lens 



ffl 



Principles of Operation 



Print Image Creation - 16 



Note: One horizontal line of an image is drawn by scanning the pulsating laser beam 
across the drum. The timing and location of the pulse is a function of the VIDEO signal 
originating from the I/O controller board. By rotating the drum and scanning 
additional lines, a two-dimensional image is built. The resolution of a laser printer is 
determined by the number of pixels per inch (in the horizontal direction) and the 
number of scans per inch (in the vertical direction). The LaserWriter 12/640 PS 
has a resolution of 600 x 600. 



Direction of Paper 



-UtX; 




600 scans/ inch 



ffl 



Principles of Operation 



Mechanical Drive - 17 



Mechanical Drive 

The generation and transmission of mechanical drive in the LaserWriter 12/640 PS is 
shown in the diagram below. 



Pickup Motor 



Gear cluster in the 
pickup drive assembly 
transmits the drive 
force to the rollers 
shown to the right. 



Cassette 
Pickup Roller 



Cassette 
Feed Roller 



Preregistration 
Feed Roller 



Manual Feed 
Pickup Roller 



Main Motor 



Gear cluster in the 
main drive assembly 
transmits the drive 
force to the rollers 
shown to the right. 



Registration 
Feed Roller 



Photosensitive 
Drum 



Drive Transfer 
Assembly 



Transfer Roller 




Fuser Roller 




Delivery Rollers 



m 



Principles of Operation 



Mechanical Drive - 18 



1 Pickup Motor Mechanical Drive (Part 1 of 2) 

The drive force generated by the pickup motor is transmitted to the cassette and 
preregistration feed rollers and to the cassette feed clutch gear via the pickup drive 
assembly. The rotation of the cassette pickup roller is controlled by the cassette feed clutch 
gear and the cassette feed solenoid. 



Pickup Drive Assembly 



Pickup Motor 



Cassette Feed 
Clutch Gear 




Cassette Pickup Roller 



20T Idler Gear Cassette Feed Roller 



ffl 



Principles of Operation 



Mechanical Drive - 19 



2 Pickup Motor Mechanical Drive (Part 2 of 2) 

The drive force generated by the pickup motor is also transmitted to the manual feed clutch 
gear via the pickup drive assembly. The rotation of the manual feed pickup roller is 
controlled by the manual feed clutch gear and the manual feed solenoid. 



Manual Feed Solenoid 



Pickup Motor 




Manual Feed Clutch Gear 



Pickup Drive Assembly 



Manual Feed Pickup Roller 



m 



Principles of Operation 



Mechanical Drive - 20 



3 Main Motor Mechanical Drive (Part 1 of 3) 

The drive force from the main motor is transmitted to the registration feed roller via the 



main drive assembly. 



Registration Pinch Roller 



Main Drive Assembly 




Registration Feed Roller 



Main Motor 



ffl 



Principles of Operation 



Mechanical Drive - 21 



4 Main Motor Mechanical Drive (Part 2 of 3) 

The drive force from the main motor is also transmitted throught the main drive assembly 
to the photosensitive drum, and from the drum to the transfer roller. 



Photosensitive Drum 




Main Drive Assembly Main Motor 



m 



Principles of Operation 



Mechanical Drive - 22 



5 Main Motor Mechanical Drive (Part 3 of 3) 

The drive force from the main motor is also transmitted to the fuser roller drive gear and 
the delivery assembly drive gear via the drive transfer assembly. When the toner cartridge 
is removed, the idler gear opens the path of drive force transmission, thus cutting off 
mechanical drive to the fuser assembly. 



Toner Cartridge 



Delivery Roller Shaft 



Delivery Assembly 
Drive Gear 



Drive Transfer Assembly 




Fuser Assembly 



Main Motor 



Main Drive Assembly 



I -ffll Principles of Operation Function of Major Components - 23 

Function of Major Components 

The function of the major components of the LaserWriter 12/640 PS is briefly described 
below. The components are divided into the following seven blocks, which correspond to the 
exploded views that appear in the exploded view chapter. 

Cassette (Deckl) 

Paper Transport 

Fusing and Paper Exit 

Drive & Xerographic 

Electrical 

Frame 



Cassette (Deck 1) 
Paper Cassette 

The cassette holds cut sheets of plain paper. Envelopes must be fed from the multipurpose 
tray or the optional envelope cassette, and post cards must be fed from the multipurpose 
tray. 

The cassette has an adjustable paper guide at the left rear. By adjusting this rear paper 
guide to the size of the paper used, individual actuator tabs on the left side of the cassette are 
engaged, thereby actuating the corresponding microswitch on the cassette sizing assembly 
board. 

The cassette has a slot that allows passage of paper from the optional lower deck. 

Cassette Sizing Assembly 

Three paper size microswitches and the leaf spring actuator are mounted onto the cassette 
size assembly printed circuit board. 

Each microswitch is on when it is being pressed by the spring actuator. The size of paper 
(or a no-cassette-present state) is detected by the combination of on and off switches. 



jffij Principl 



es of Operation 



Function of Major Components - 24 



Cassette (Deck 1) 




Microswitches 



Cassette Sizing Assembly 



Cassette 




Leaf Spring Actuator 



m 



Principles of Operation Function of Major Components - 25 



Paper Transport (1 of 2) 

Pickup Drive Assembly 

The pickup drive assembly is responsible for mechanical drive to the cassette and manual 
feed pickup rollers and to the cassette and preregistration feed rollers. It is powered by the 
pickup motor. Contained within the assembly itself are the two feed rollers and the cassette 
feed solenoid. 

Main Drive Assembly 

The main drive assembly is responsible for all mechanical drive from the registration 
roller through paper delivery. It is powered by the main motor. 

Drive Transfer Assembly 

The drive transfer assembly is the gear train that transfers mechanical drive from the 
main motor to the fuser assembly, delivery roller shaft, and photosensitive drum. An idler 
gear is located along the path of the drive force transmission to the fuser. The idler gear 
closes the path when the toner cartridge is installed 

Registration Feed Roller 

The registration feed roller, which is driven by the operation of the main drive assembly, 
feeds paper in concert with the registration pinch roller. The pinch roller is spring-loaded 
but passive. It receives no mechanical drive. 

Registration Sensor/Actuator 

The registration sensor is mounted to the power supply assembly. The registration actuator 
is mounted to the frame. The sensor detects when paper reaches the registration position. 
The signal of the registration sensor is used to position paper in synch with the toner image 
on the drum. 

Preregistration Sensor/Actuator 

The preregistration sensor is mounted to the power supply assembly. The actuator is 
mounted to the chute registration assembly. The preregistration sensor detects when paper 
reaches the preregistration position. 

Paper Deflector Solenoid 

Switches the direction of the paper deflector guide. 

Paper Deflector Guide 

This guide is on the delivery side of the fuser. It controls whether paper passes into the 
duplexer/ face-up tray or outward onto the output tray. 



Ifflj Principl 



es of Operation 



Function of Major Components - 26 



Paper Transport (1 of 2) 



Main Drive Assembly 

Main Motor 

Pickup Motor 

Preregistration Feed Roller 
Cassette Feed Roller 

Pickup Drive Assembly 
Cassette Feed Solenoid 



Preregistration 
Actuator A 

Preregistration 
Actuator B 



Registration Pinch Roller 
Registration Feed Roller 

Paper Deflector Solenoid 

Paper Deflector Guide 




Cassette Pickup Roller 



Registration Actuator 
Registration Sensor 



Registration Registration 

Feed Roller Pressure Roller 



Preregistration Pinch Roller 
Preregistration Feed Roller 

Cassette Pinch Roller 
Cassette Feed Roller 




Cassette Pickup Roller 



gi 



Principles of Operation Function of Major Components - 27 



Paper Transport (2 of 2) 
Multipurpose Frame Assembly 

The multipurpose frame assembly includes the manual feed solenoid, manual feed clutch 
gear, manual feed pickup roller, separation pad, and the manual feed paper-present sensor 
and actuator. 



jffij Principl 



es of Operation 



Function of Major Components - 28 



Paper Transport (2 of 2) 



Manual Feed Solenoid 




Manual Feed Paper-Present 
Actuator 



Manual Feed Paper- Present 
Sensor 



Multipurpose Frame 
Assembly 



Manual Feed Pickup Roller 



Separation Pad 



m 



Principles of Operation Function of Major Components - 29 



Fusing and Paper Exit 

Fuser Assembly 

The major parts contained within the fuser assembly include the fuser heater bulb, fuser 
roller, thermostat, fuse, and temperature sensor assembly. 

The fuser heater bulb is located inside the fuser roller. Power to the bulb is switched on 
and off so that the temperature of the fuser roller surface is kept constant. When the 
temperature of the fuser rises to the predetermined upper limit temperature, the power 
supply is switched off. This safeguard is known as first-stage overheat protection. 

The fuser roller applies the heat for melting and fusing the toner to paper. It is connected to 
the frame ground through a diode so that negative charge flows, thereby preventing the 
toner image from being disturbed during the fusing process. 

The thermostat is a part of the fuser bulb circuit and provides the second-stage overheat 
protection. If the first-stage overheat protection fails to prevent overheat and the 
thermostat reaches the predetermined temperature, the contacts of the thermostat open to 
break the circuit between the fuser bulb and the power supply. 
The fuse is also a part of the fuser bulb circuit and provides the third-stage overheat 
protection. If the first and second stage protection both fail to prevent overheat and the fuse 
reaches the predetermined temperature, the fuse melts to open the circuit between the 
fuser and the power supply. 

The temperature sensor is a resistor whose resistance varies rapidly with temperature. It 
is positioned in contact with the surface of the fuser roller. Power to the fuser bulb is 
switched on and off so that the temperature of the surface of the fuser roller is kept 
constant. 

Fuser Pressure Roller 

The fuser pressure roller is a sponge roller covered with a tube. It is located beneath the 
fuser assembly and is spring-loaded to apply pressure against the fuser roller as paper 
passes. The fuser pressure roller is not mechanically driven. 

Fuser Exit Sensor/Actuator 

The fuser exit sensor is actuated as paper exits the fuser assembly but before paper reaches 
the paper deflector guide. 

Delivery Sensor/Actuators 

The delivery sensor is actuated as paper reaches the delivery rollers. 

Delivery Roller Shaft 

The delivery roller shaft holds three fixed delivery rollers that feed paper through to the 
output tray on the top of the printer. 



Ifflj Principl 



es of Operation 



Function of Major Components - 30 



Fusing and Paper Exit 



Fuser Exit Actuator 



Delivery Rollers 



Fuser Assembly 




Fuser Exit Sensor 



Temperature 
Sensor Assembly 




Fuser Roller 



Pressure Roller 



Heater Bulb 



Fuser Roller 




. Fuser Exit 
Pinch Roller 



Fuser Exit Roller 



Pressure Roller 



gj 



Principles of Operation Function of Major Components - 31 



Drive and Xerographic 

For full description of the components in this section, see the "Print Image Creation" topic. 
Laser/Scanner Assembly 

The laser/ scanner assembly includes the laser diode, scanner, lenses, and mirrors. 

Note: The laser/ scanner assembly is a precision optical system. Never open the 
cover. Touching the parts may result in permanent damage to the components. 

Mirror Assembly 

The mirror assembly includes the start-of-scan sensor (SOS) and the stationary mirror 
that reflects the beam from the scanner mirror onto the photosensitive drum. 

Toner Cartridge 

The toner cartridge consists of a photosensitive drum and a toner container integrated into 
one unit. It includes the following major components. 

Photosensitive Drum 

Bias Charge Roller (BCR) 

Attraction Roller 

Charging and Metering Blade (CMB) 

Cleaning Blade 

Laser Shutter 

Transfer Roller 



Ifflj Principl 



es of Operation 



Function of Major Components - 32 



Drive and Xerographic (1 of 2). 



Mirror Assembly 




Transfer Roller 



Toner Cartridge 



Latch Shaft Flange 



Toner Cartridge Latching Mechanism 



Ifflj Principl 



es of Operation 



Function of Major Components - 33 



Drive and Xerographic (2 of 2) 



Collimator Lens 



Start-of-Scan Sensor (SOS) 



Mirror Ml 



Laser Diode 



Cylinder Lens 



Hexagonal Mirror 



Scanner Assembly 




Mirror Assembly 



Laser/ Scanner Assembly 



Toner Cartridge 



CM Blade 



Bias Charge Roller 



Cleaning Blade 




Photosensitive 
Drum 



m 



Principles of Operation Function of Major Components - 34 



Electrical 

Power Supply Assembly 

The power supply assembly is a large multifunctional circuit board located in the lower 
section of the engine. Listed below are its major components. 

Low-voltage power supply (LVPS): The LVPS generates stabilized DC voltages of 5 V, 
12 V, and 24 V and supplies these voltages to the electrical components of the printer. 

High-voltage power supply (HVPS): The HVP5 generates AC and DC high voltages for 
charge, development, transfer, and discharge in the print process. Those voltages are 
supplied to the bias charge roller, attraction roller, transfer roller, and detack saw. 

Interlock switch: This switch opens the supply circuits of 24 VDC and 5 VDC (+B) for 
driving the laser diode. 

Cassette paper-present sensor: This sensor is actuated by the cassette paper-present 
actuator and detects when the cassette runs out of paper. 

Power inlet: The power inlet is hard-wired directly to the circuit board. 

DC Controller Board 

The DC controller board controls the whole operation of the printer. Listed below are its 
major functions: 

Communication with the I/O board 

Collection of the information from the sensors and switches. 

Control of the laser/ scanner assembly, fuser assembly, drive assemblies, and 
solenoids. 

Control of the print sequence. 

Distribution of the low DC voltages to electrical components from the power supply 
assembly. 

Fan 

The fan forces the air out of the printer to prevent overheating. There is only one fan in the 
LaserWriter 12/640 PS. 



Ifflj Principl 



es of Operation 



Function of Major Components - 35 



Electrical 



DC Controller Board 



I/O Controller Board 



Registration 
Sensor 



Cassette Paper- 
Present Sensor 



Preregistration 
Sensor 




Power 
Inlet 



Power Supply 
Assembly 




Interlock Switch 



m 



Principles of Operation Function of Major Components - 36 



Frame 

When the top cover closes, the seven events described below take place. 

Cover Interlock Actuator 

Top cover closure actuates the interlock switch on the power supply assembly. There are 
three components that work together to actuate this switch. 

Top cover actuator: The thin plastic post built into the top cover. 

Spring-loaded actuator: The vertical assembly that transfers actuation downward. 

Actuator arm: The arm that contacts the interlock switch on the power supply 
assembly. 

Laser Shutter 

A plastic post built into the top cover extends through a cutout in the top of the laser/ 
scanner assembly. The laser shutter facing the mirror assembly opens, thus allowing the 
laser beam to leave the laser/ scanner assembly. 

Mirror Assembly Shutter 

A plastic post built into the top cover presses open the shutter that covers the mirror 
assembly. Unless this shutter and the one above are in an open position, the laser can not 
reach the photosensitive drum. 

Cover Latch 

Two latches on the chassis hook onto the underside of the cover to assure tight closure of the 
cover. The right cover latch has an integral spring-loaded plate that is actuated by the top 
cover release lever. 

Jam Release Plate 

The top cover presses against the surface of the jam release plate to the left of the laser/ 
scanner assembly. In a cover-closed position, this plate presses against the 
preregistration pinch roller assembly, resulting in a tight gripping surface for paper feed. 
In a cover-open condition, the pinch roller does not grip the paper, thus facilitating 
removal of paper jams. 

Toner Cartridge Latching Mechanism 

Top cover closure actuates a cam mechanism that presses and stabilizes the toner cartridge. 
See the "Drive and Xerographic (1 of 2)" illustration. 

Fuser Idler Gear Actuation 

There is a spring-loaded lever on the drive transfer assembly that controls the position of 
the fuser idler gear. When the top cover is closed, this lever is pressed, thus completing 
the drive train to the fuser assembly. 



Ifflj Principl 



es of Operation 



Function of Major Components - 37 



Frame 



Fuser Idler 
Gear Actuation 



J am Release Plate 



Mirror Assembly 
Shutter 




Laser 
Shutter 



Cover 
Latch 



Toner Cartridge 
Latching Mechanism 



Cover Interlock 
Actuator 



Interlock Switch 
(on Power Supply Assy.) 





Actuator Arm 



V 



Top Cover Actuator 
(Spring-Loaded) 



Ifflj Principl 



es of Operation 



Function of Major Components - 38 



General Wiring Diagram 



Fuser Assembly 



Thermistor 



STS2 



Delivery 
Sensor 



Fuser Exit 
Sensor 



m rm 



p/j 

285 



P/J 
281 









(I) 






o 




J242 


(I) 




-2 


LL 












til 






(11 






^= 






C/J 


P242 














(11 






X 






0) 






Q. 

3 




,124? 


rj 




-1 








i- 







p/J 

232 



Cassette Size 
Sensing Assembly 



Cassette Size 
Microswitoh 



P231 



P/J234 



P/J 
234-1 



J2341 



P/J236 



P/J 
234-2 



J2342 



Cassette 

Feed 
Solenoid 



P/J 
236-1 



J236-2 



Manual 

Feed 

Solenoid 



I 



P/J 
236-3 



LnnJ 

Manual Feed 

Paper-Present 

Sensor 



M 
Pickup Motor 

M 
Main Motor 



STS1 



J292 



P/J291 



P/J 
28 



P/J29 



P/J 
23 



P/J 
21 



DC Controller 
Board 



p/j 

26 



P/J 
24 



P/J 
30 



P/J 
25 



P/J 31 



P/J 
22 



I/ O Board 



Fuser Heater 

-TJUL-i 



P/J 11 



Main 
Switch 



No- 
lo- 




FG 



Inlet 



P/J 
222 



Preregistration 
Sensor 



Registration 
Sensor 



Cassette Paper- 
Present Sensor 



Fan 



Toner 
Cartridge 



Power Supply 
Assembly 



(not used) 



Laser/ Scanner 
Assembly 



p/j 

262 



Laser 
Diode 



P/J 
261 



Scanner 
Motor 



P/J 
301 



Start-of-Scan 
Sensor 



Paper Deflector 
Solenoid 



jffij Principl 



es of Operation Function of Major Components - 39 



Ports 




LocalTalk 
Port 



Ethernet Port 



Parallel Port 
Communication Switch 



Service Source 




Troubleshooting 



LaserWriter 12/640 PS 



<m* 



m 



Troubleshooting About the Status Panel - 1 

About the Status Panel 



Ready I 1 (J) 



The LaserWriter 12/640 PS has a status panel that consists of 
three LEDs. The status reported through the LEDs is generated by 
the I/O controller board based upon signals that the board receives 
from the printer sensing system and other engine monitoring 
mechanisms. There are two types of reporting. 

Paper I — k • End-user reporting consists of LED arrays that can be 

0ut observed by end users without need of special tools. This type of 

Paper | q* reporting can be broken down into POST and PostScript 

' am reporting (see following topics). 

• Service technician reporting consists of LED arrays that can 
only be observed through the use of a special tool. This 
reporting is also referred to as EPOST (see topic later in this 
chapter). Whereas end-user reporting can help you in 
troubleshooting over the phone, EPOST requires that you be at 
the printer location. 



m 



Troubleshooting POST (Power-On Self Test) - 2 

POST (Power-On Self Test) 

When you switch on power, all the status panel LEDs illuminate 
briefly. This confirms that power is getting to the status panel and 
that all LEDs are operational. All LEDs then extinguish and come 
back on. This marks the start of POST. 

POST is a set of diagnostic procedures that are written into 
firmware on the I/O controller board. POST executes in the first 
10 seconds of startup and checks the following three areas of the 
printer in order: 

• Stage ll/O controller (ROM & SIMMs) 

• Stage 2 1/0 controller (miscellaneous circuitry) 

• Stage 3 D/C controller board 



<\U\* 



m 



Troubleshooting 



POST (Power-On Self Test)/ Stage Failure/ POST - 3 




POST Example 



Stage Failure/POST 

POST extinguishes the LEDs from top to bottom as each test stage 
passes. (The Ready LED is considered here to be the top LED). In a 
functional printer, the testing process takes about 40 seconds, 
after which control passes to PostScript code in ROM and the 
normal warm-up continues (see "PostScript Reporting" in this 
chapter). 

However, if POST detects a fault during any stage, the status panel 
enters an error state and flashes the bottom two LEDs forever. 
Making note of the stage from which this error array first 
appears can help you choose the modules to bring on a service call. 

For example, suppose failure occurs during stage two (only the 
top LED had extinguished before the error array appears). This 
indicates an I/O board failure, so a replacement board should 
definitely accompany you on site. 



<<■► 



m 



Troubleshooting PostScript Reporting - 4 



PostScript Reporting 



PostScript reporting starts as soon as POST is completed. Most of 
the time, PostScript will report according to the literal 
designation of the LED. (For example, the paper-out LED 
illuminates when the paper cassette is empty). However, there 
are some instances where closer observation is critical in 
interpreting the status panel. 

• Solid ready light: In some cases, the ready light will illuminate 
for as long as 15 seconds before a PostScript fault is reported. 
Make sure to wait this extra time for PostScript to execute 
before shutting down to perform further troubleshooting. 

• Behavior before PostScript error: As with stage- re porting 
during POST, it is sometimes necessary to note what occurs 
before the error array first appears. The chart on the 
following page notes where this is important. 



<\U\* 



m 



Troubleshooting 



PostScript Reporting/ End-User Error Codes - 5 



End-User Error Codes 



Array 



Description 



Explanation 



^H U 


1 | q Ready LED on Printer is ready 




1 1 ^v 




m* u 


1 | o Ready LED flashes Printer is warminq up or processinq a iob 1. 




1 1 -&\ 






1 | o Paper-Out and An error has been detected in POST. Observation 


1 r o Paper-J am LEDs of LED behavior prior to this array can isolate the 


IZZM 8'v flash fault to one of three general area (see "POST") 2 


' 




1 1 u 




1 | d All LEDs off The top cover is open. 












rapei -out LbU .. .. . . . „ . -a 


1 □ ■„ • u No paper or cassette is not installed J . 


illuminates 


1 1 erv 






1 1 1 ) r» i i i-r^ n ■ 1 ■ ■ j. l i. ■ 1 


rapei -j am LbU rapei is jammed in piintei oi tonei caitiioge 


1 1 Q ...'." . . ' . . ' A 


illuminates is missing H 










raper-j am LbU , , . . 


I | o „ , Laser/ scanner assembly error. 


rias'iPS 





If the ready LED flashes forever, turn off the printer, disconnect it from the 
network, and restart the printer. If the flashing does not recur, the problem 
is most likely with networking or host computer software. If the flashing occurs 
with a stand-alone printer, a faulty fan may be the problem. 

If this array is preceded by the following behavior, the problem is likely with 

the fuser assembly: ready LED comes on; ready LED flashes; fan comes on; and 

paper for startup page is picked up but jams in the printer. 

In some cases, this array can result from a faulty scanner motor or main motor. 

For some residual paper jams (for example, where a jam exists in the delivery 
area at time of startup), the printer may exhibit a ready state to the point where 
the fan will come on and the paper for the startup page is picked up. 



<*> 



m 



Troubleshooting EPOST (Extended Power-On Self Test) - 6 

EPOST (Extended Power-On Self Test) 

EPOST behaves exactly like POST in that it checks the same three 
areas in the same order and displays an error array if a fault is 
detected. However, EPOST has more extensive testing and its error 
arrays are completely different. When a fault is detected during 
EPOST, all LEDs extinguish and the status panel will loop through 
the following sequence until you switch off power: 

• All LEDs On for approximately one second 

• All LEDs Off for approximately one second 

• EPOST Error Code for approximately one second 

• All LEDs Off for approximately two seconds, then repeat loop 

If no error is detected by EPOST, an EPOST test page will print 
before control is passed on to the PostScript interpreter (if a 
duplex unit is attached, two double-sided pages will print). 



<\U\* 



m 



Troubleshooting EPOST (Extended Power-On Self Test) - 7 



i ,.n 



w 



Initiating EPOST 

To initiate EPOST, you must have the printer rollback test plug 
(P/N 922-1489). This test plug is colored bright green to 
differentiate it from the older version black plug. Do not use the 
black plug on the LaserWriter 12/640 PS. It won't harm 
anything; it just won't work. 

Switch off the printer and install the test plug into the LocalTalk 
port on the back of the I/O controller board. Switch the printer 
back on. 



<\U\* 



m 



Troubleshooting 



EPOST (Extended Power-On Self Test) - 8 




EPOST Example 1 



Stage Failure/EPOST 

An EPOST error code can either illuminate solidly (for I/O 
controller failures) or flash (for engine failures). The chart on 
the next page shows the possible error arrays. The "EPOST 
Example" animations demonstrate two of the combinations. 

The "Example 1" animation simulates an I/O board error. Notice 
how the EPOST announcement sequence (all LEDs on for a second 
then all LEDs off for a second) is followed by a paper jam LED that 
illuminates solidly for about a second. 

The "Example 2" animation simulates a DC controller board 
error. Notice how the EPOST announcement sequence is followed 
by a paper jam LED that flashes for about a second. 




EPOST Example 2 



<\U\* 



m 



Troubleshooting 



EPOST (Extended Power-On Self Test)/ EPOST Error Codes - 9 



EPOST Error Codes 

All LEDs on for a second, then off for a second, followed by a 
one-second display of... 



1 o 



...Solid J am LED 
= 1/0 Controller Board Error 



J □ 



...Flashing J am LED 
= DC Controller Board Error 






.Flashing Out LED 
= Fuser Assembly Error 



J u 



...Solid J am & Out LEDs 
= ROM (I/O Controller) Error 



□ 



...Flashing J am & Out LEDs 
= Laser/ Scanner Error 



1 □ 



.Solid Ready LED 
= General SIMM Error 



1 □ 
3 rv 



.Flashing Ready LED 
= Fan Error 



J Q 



.Solid Ready & J am LEDs 
= SIMM (A/B) Error 



J o 



.Flashing Ready &Jam LEDs 
= Miscellaneous Engine Error* 



Q 



...Solid Ready & Out LEDs 
= SIMM (C/D) Error 



o 



...Flashing Ready & Out LEDs 
= Duplexer Error 



o 



.All Three LEDs Flashing 
= Toner Cartridge Missing 



* Miscellaneous engine error includes paper jams, top lid open, missing paper 
cassette, no paper, or duplexer open. 

Note: Always check for paper jams when a miscellaneous engine error occurs. 
Many times paper is picked up to do a test print and an error occurs. When 
you restart, the test will detect the paper jam first if the jam has not been 
removed. 



<<■► 



a 



Troubleshooting 



Cleaning the Mirror - 10 



Cleaning the Mirror 



There is a small peach-colored square cleaner built into the 
mirror assembly. Slide this square back and forth to remove 
particles from the mirror. 




Mirror 
Cleaner 



<<■► 



m 



Troubleshooting 



Duplexer J arms - 11 



Duplexer Jams 



The paper guide provided with the duplexer must be installed 
during setup. (Refer users to page 137 of the user manual). If you 




Paper Guide 



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m 



Troubleshooting 



Duplexer J aims - 12 



fail to install this guide properly, jamming will frequently occur 
as paper enters the duplexer from the printer. Be sure that the 
two locking connectors are also fully snapped into place. 




Locking Connectors 



<\U\* 



m 



Troubleshooting Duplexer J aims - 13 



If accordion-style jamming still occurs in the duplexer after 
proper installation of the paper guide, replace the vertical 
duplexer assembly (P/N 922-2001) 



<<■► 



m 



Troubleshooting Printing with 8.3 Driver/ EPOST Error Codes - 14 



Printing with 8.3 Driver 

For purposes of troubleshooting paper feed, you can print with the 
LaserWriter 8.3 driver from Mac OS computers. Simply copy the 
PPD for the LaserWriter 12/640 PS into the Printer 
Descriptions folder in the System Folder, select the printer 
through the Chooser, and click on Setup. 

You can print duplex jobs by clicking on the Options button in the 
print dialog and making the appropriate selection. However, you 
cannot print to the face-up tray with the 8.3 driver. 

Note : The LaserWriter 12/640 PS PPD is available on the J une 
1996 Service Source CD (path: Service Source:Service 
Manuals:Clips). 



<<■► 



m 



Troubleshooting Out of Paper in Multipurpose Tray - 15 

Out of Paper in Multipurpose Tray 

If you are trying to print from the standard cassette and get an 
error message saying that there is no paper in the multipurpose 
tray, the problem may be in cassette setup. 

There is a paper-length guide at the end of the cassette that must 
be adjusted for letter size paper (the position as shipped is for A4 
paper). When the AutoSelect feature built into PostScript 
searches for letter size paper, the cassette will be passed over and 
the controller assumes that the paper should be in the 
multipurpose tray. 

To rectify this situation, make sure that the length guide is 
adjusted for letter size paper, see the next page for the graphic. 



<\U\* 



a 



Troubleshooting Out of Paper in Multipurpose Tray/ EPOST Error Codes - 16 




<m* 



m 



Troubleshooting Multipurpose Tray Paper J arms - 17 

Multipurpose Tray Paper Jams 

There have been a number of reported problems with the 
multipurpose tray and its associated components. In the process of 
resolving these problems, service providers may inadvertently 
dislocate the solenoid flapper or actuator that is responsible for 
releasing the multipurpose tray paper pickup roller so that it can 
complete its paper pickup cycle. When this occurs the paper 
pickup roller rotates constantly resulting in paper jams (if paper 
is present) and annoying noises whenever the printer is being 
used. Correcting the problem requires a service call. 

Refer to the Multipurpose Tray Paper | ams pdf. file for the 
repair procedure. 



<\U\* 



m 



Troubleshooting Testing the Print Engine without the I/O Board - 18 

Testing the Print Engine without the I/O 
Board 

Remove the 1/ O board. The DC Controller interface connects to the 
back of the I/O board. J ust below this interface board is a metal 
plate which has a grid etched into it. This grid is the key to the 
pins located on the interface just above it. 

On the DC controller interface, locate the pin marked TP (test 
print). J umper the pin "TP" to one of the pins marked "G" 
(ground). Be careful to jumper the correct pins since some pins 
carry DC voltage. 

You can also try forcing a test print without removing the I/O by 
starting with the test print pins (on the I/O board) jumpered, and 
then applying power. If you start with the pins jumpered before 
turning the printer on, this should bypass the power-on self test. 



m 



Troubleshooting False Paper J am Error with Startup Page - 19 

False Paper Jam Error with Startup Page 

Symptom: A false paper jam error occurs when the 
LaserWriter 12/640 tries to print the startup page. No paper is 
picked up. EPOST reports a DC Controller error. When the DC 
controller board is replaced, the problem remains. Upon 
initiating a service test print, the motor will spin for about a 
second and then will stop with no test page output. 

Discussion : Observe the pickup solenoid through the small hole 
in the shield that covers the pickup drive assembly, and initiate a 
service test print. You should see the pickup motor spin, and about 
a second later see the solenoid trigger. If it does not, you either 
have a bad solenoid, bad cassette size sensor board, or a bad cable 
that runs between the solenoid and the sensor board. In the case of 
the bad cassette size sensor board, it can cause EPOST to display a 
DC controller error. 



<\U\* 



he? 



Troubleshooting Print Quality Problems - 1 



Image Quality Problems 



It can be easily determined whether an image quality problem is being caused by the print engine or by the 
I/O controller board by producing a service test page. The service test page can be generated by jumper- 
ing the two pins of connector J 101 on the I/O controller board. 

If the test page is normal, but the regular prints have an image quality problem, the problem is probably 
with the I/O controller board. If the test print has also the image quality problem, the problem is probably 
in the print engine. 

When troubleshooting an image problem, produce a test print using letter size or A4 paper, exactly iden- 
tify the symptom, and isolate the problem by referencing the accompanying troubleshooting tables. 

If the tables do not lead you to a solution to the problem, examine each part listed in the initial analysis of 
the table corresponding to the problem. The fault is probably among those parts. Replace the part or parts 
that in your judgment will most likely resolve the problem. 



Roller Diameters 



For a listing of the diameters of the rollers in the LaserWriter 12/ 640 PS, see page 13 in the Principles of 
Operation chapter. Knowing these diameters can assist in troubleshooting repetitive horizontal print 
defects. 

List of Troubleshooting Tables 

The troubleshooting tables cover the following typical fourteen image quality problems: 

Table P-l Light Prints 

Table P-2 Blank Prints 

Table P-3 Black Prints 

Table P-4 Vertical Band Deletions 

Table P-5 Horizontal Band Deletions 

Table P-6 Vertical Streaks 

Table P-7 Horizontal Streaks 

Table P-8 Spot Deletions 

Table P-9 Spots 

Table P-10 Residual Image 

Table P-ll Background 

Table P-l 2 Skewed Image 

Table P-13 Damaged Prints 

Table P-14 Unfused Image 

Table P-l 5 No PhotoGrade 

Table P-16 No Duplex Printing 

Table P-17 Duplex Page Upside-Down 

Table P-18 No Multipurpose Tray Printing 

Note: Vertical refers to the direction of paper travel. Horizontal refers to the direction perpendicular to 
the direction of paper travel. 



he? 



Troubleshooting 



Print Quality Problems - 2 



P-l Light Prints 




Problem 

The overall image density is lighter than normal. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assy 

• Mirror Assembly • Laser/ Scanner Assy • DC Controller Board 

• Fuser Assembly • Fuser Pressure Roller • Static Eliminator 

• Top Cover 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


3 


Dirty reflecting mirror 

Is the problem solved if you use the peach-colored slider 
(built into the mirror assembly) to wipe the mirror clean? 


Clean the mirror. 


4 


Drum ground 

Is the toner cartridge drum grounded securely? 

* Check the drum ground path: drum > drum shaft pin > 


Restore the continuity of the 
drum ground path. 


5 


Laser beam path 

Are there obstructions or contamination on the laser beam 
path from the laser/ scanner assembly to the Drum? 


Remove the obstructions or 
contamination. 


6 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


7 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Go to FIP-2.18 Power 
Supply Assy (HV part) 
failure. 


8 


Transfer 

Is the toner image on the drum transferred normally on the 
paper? 

* Switch off the printer power while the transfer is in 
progress, and visually check the toner image on the drum. 


Go to FIP-2.18 Power 
Supply Assy (HV part) 
failure. 



he? 



Troubleshooting 



Print Quality Problems - 3 



P-2 Blank Prints 



Problem 

The entire print is blank. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer version, 
correctly installed, not damaged, deformed or contaminated, or free of foreign 
objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assy 

• Mirror Assembly • Laser/ Scanner Assy • DC Controller Board 

• Fuser Assembly • Fuser Pressure Roller • Static Eliminator 

• Top Cover 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


2 


Drum ground 

Is the toner cartridge drum grounded securely? 

* Check the drum ground path: drum > drum shaft pin > 


Restore the continuity of the 
drum ground path. 


3 


Laser beam path 

Are there obstructions or contamination on the laser beam 
path from the laser/ scanner assembly to the Drum? 


Remove the obstructions or 
contamination. 


4 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


5 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Go to FIP-2.18 HV failure. 


6 


Transfer 

Is the toner image on the drum transferred normally on the 
paper? 

* Switch off the printer power while the transfer is in 
progress, and visually check the toner image on the drum. 


Go to FIP-2.18 Power 
Supply Assy ( HV part) 
failure. 



he? 



Troubleshooting 



Print Quality Problems - 4 



P-3 Black Prints 




Problem 

The entire print is black. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer version, 
correctly installed, not damaged, deformed or contaminated, or free of foreign 
objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assy 

• Mirror Assembly • Laser/ Scanner Assy • DC Controller Board 

• Fuser Assembly • Fuser Pressure Roller • Static Eliminator 

• Top Cover 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


2 


Charging 

Use a sheet of paper to cover the window through which the 
laser beam is emitted from the laser/ scanner assembly. 

Does the problem still occur? 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


3 


Laser/ scanner assy 

Use a sheet of paper to cover half of the window through 

which the laser beam is emitted from the laser/ scanner 

assembly. 

Does the problem still occur? 


Replace laser/ scanner 
assembly. If problem 
persists, replace DC 
controller board. 



-& 



Troubleshooting 



Print Quality Problems - 5 



P-4 Vertical Band Deletions 




Problem 

There are areas of the image that are extremely light or missing entirely. These 
missing areas form wide bands that run vertically along the page, in the direction 
of paper travel. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy 

• Mirror Assembly • Laser/ Scanner Assy 

• Fuser Assembly • Fuser Pressure Roller 

• Top Cover 



Transfer Roller Assy 
DC Controller Board 
Static Eliminator 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Dirty reflecting mirror 

Is the problem solved if you use the peach-colored slider 
(built into the mirror assembly) to wipe the mirror clean? 


Clean the mirror. 


2 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


3 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


4 


Paper usability 

If the problem still occurs after the toner cartridge is 
replaced, again replace the toner cartridge with another new 
one, and replace paper with standard paper. 

Is the problem solved? 

* When acid paper is used, this problem may occur because of 
a component of paper. 


Replace paper with standard 
paper. 


5 


Paper path 

Are there obstructions such as burrs or objects or contami- 
nation on the paper path? 


Remove the obstructions or 
replace the component. 


6 


Laser beam path 

Are there obstructions or contamination on the laser beam 
path from the laser/ scanner assembly to the Drum? 


Remove the obstructions or 
contamination. 


7 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


7 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 



he? 



Troubleshooting 



Print Quality Problems - 6 



P-5 Horizontal Band Deletions 



h\ i 



Problem 

There are areas of the image that are extremely light or missing entirely. These 
missing areas form wide bands that run horizontally across the page and parallel 
with the direction of paper travel. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy 

• Mirror Assembly • Laser/ Scanner Assy 

• Fuser Assembly • Fuser Pressure Roller 

• Top Cover 



Transfer Roller Assy 
DC Controller Board 
Static Eliminator 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock 
paper in a dry place. 


2 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a new 
one? 


Replace the toner 
cartridge. 


3 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the area 
upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


4 


Main drive assembly and drive transfer assembly 

Does each gear of the drive assemblies rotate normally? 

* Remove the fuser assembly and the toner cartridge. Rotate the 
gear above at the rear of the drive assembly by hand in the rear- 
ward direction. Visually check the rotation of the gears. 


Replace the drive 
assembly. 


5 


Registration roller assembly 

Does the registration roller assembly rotate normally? 

* Open the cover and remove the toner cartridge. Rotate the 
registration roller by hand. 


Replace the registration 
roller assembly. 


6 


Fuser assembly 

Do the fuser heater roller and gears of the fuser assembly rotate 
normally? 

* Remove the fuser assembly. Rotate the fuser heater roller gear 
by hand and check their rotation by eye. 


Replace the fuser 
assembly. 


7 


Transfer roller assembly 

Are there foreign objects or contamination on the roller portion of 
the transfer roller assembly? 


Replace the transfer 
roller assembly. 



-& 



Troubleshooting 



Print Quality Problems - 7 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


8 


Transfer 

Is the toner image on the drum transferred normally on the paper? 

* Switch off the printer power while the transfer is in progress, 
and visually check the toner image on the drum. 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


9 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 



■ff 



Troubleshooting 



Print Quality Problems - 8 



P-6 Vertical Streaks 




Problem 

There are black lines running vertically along the page. 

Initial Analysis 

Inspect the following components. Are they compatible with your printer version, 

correctly installed, not damaged, deformed or contaminated, or free of foreign 

objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assy 

• Mirror Assembly • Laser/ Scanner Assy • DC Controller Board 

• Fuser Assembly • Fuser Pressure Roller • Static Eliminator 

• Top Cover 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


2 


Paper path 

Are there obstructions such as burrs or objects or contami- 
nation on the paper path? 


Remove the obstructions or 
replace the component. 


3 


Laser beam path 

Are there obstructions or contamination on the laser beam 
path from the laser/ scanner assembly to the Drum? 


Remove the obstructions or 
contamination. 


4 


Laser/ scanner assy 

Use a sheet of paper to cover the window through which the 
laser beam is emitted from the laser/ scanner assembly. 

Does the problem still occur? 


Replace laser/ scanner 
assembly. If problem 
persists, replace DC 
controller board. 


5 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


6 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 



he? 



Troubleshooting 



Print Quality Problems - 9 



P-7 Horizontal Streaks 




Problem 

There are black lines running horizontally across the page. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assy 

• Mirror Assembly • Laser/ Scanner Assy • DC Controller Board 

• Fuser Assembly • Fuser Pressure Roller • Static Eliminator 

• Top Cover 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


2 


Drum ground 

Is the toner cartridge drum grounded securely? 

* Check the drum ground path: drum > drum shaft pin > 


Restore the continuity of the 
drum ground path. 


3 


Charging 

Use a sheet of paper to cover the window through which the 
laser beam is emitted from the laser/ scanner assembly. 

Does the problem still occur? 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


4 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


5 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


6 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 



he? 



Troubleshooting 



Print Quality Problems - 10 



P-8 Spot Deletions 




Problem 

There are areas of the images that are extremely light or missing entirely. These 
missing areas form spots that are localized to small areas of the page. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assembly 

• Laser/ Scanner Assy • Mirror Assembly • Fuser Assembly 

• Fuser Pressure Roller 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


3 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


4 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 


5 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 



he? 



Troubleshooting 



Print Quality Problems - 11 



P-9 Spots 




Problem 

There are spots of toner all over the page. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy • Transfer Roller Assembly 

• Laser/ Scanner Assy • Mirror Assembly • Fuser Assembly 

• Fuser Pressure Roller 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


3 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


4 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 


5 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 



he? 



Troubleshooting 



Print Quality Problems - 12 



P-10 Residual Image 




Problem 

There are ghosted images appearing on the page. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy 

• Mirror Assembly • Laser/ Scanner Assy 

• Fuser Assembly • Fuser Pressure Roller 

• Top Cover 



Transfer Roller Assy 
DC Controller Board 
Static Eliminator 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


3 


Transfer roller assembly 

Are there foreign objects or contamination on the roller 
portion of the transfer roller assembly? 


Replace the transfer roller 
assembly. 


4 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 


5 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 


6 


Is the problem solved by changing the image printed or the 
vertical-and-horizontal orientation of the image? 


Since this phenomenon is 
inevitable, advise the 
customer to change the 
image printed or the 
vertical-and-horizontal 
orientation of the image. 



he? 



Troubleshooting 



Print Quality Problems - 13 



P-ll Background 




Problem 

There is toner contamination on all or part of the page. The contamination appears 
as a very light gray dusting. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Power Supply Assy • Laser/ Scanner Assy 

• Mirror Assembly • DC Controller Board • Fuser Assembly 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Charging and development 

Is the toner image on the drum normally developed? 

* Switch off the printer power while the development is in 
progress, and visually check the toner image on the drum (the 
area upstream of the transfer step). 


Replace power supply 
assembly. If problem 
persists, replace DC 
controller board. 


2 


Chute assembly BTR ground 

Is the chute assembly bias transfer roller grounded 
securely? 


Restore the continuity of the 
chute assembly BTR ground. 


3 


Fuser assembly ground 

Is the fuser assembly grounded securely? 


Restore the continuity of the 
fuser assembly ground. 


4 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 



he? 



Troubleshooting 



Print Quality Problems - 14 



P-12 Skewed Image 




Problem 

The printed image is not parallel with the sides of the page. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Toner Cartridge • Transfer Roller Assy • Fuser Assembly 

• Regist. Roller Assy • Feeder Unit • Cassette Pickup Roller 

• Paper Cassette • Laser/ Scanner Assy • Mirror Assembly 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper feed 

Is the paper cassette installed correctly, and is the paper 
correctly loaded? 


Reload the paper and rein- 
stall the cassette. 


2 


Paper path 

Are there obstructions such as burrs or foreign objects or 
contamination on the paper path? 


Remove the obstructions or 
replace the component. 


3 


Feeder roller 

Does the feeder roller feed the paper correctly? 


Replace the feeder roller. 


4 


Paper path rollers 

Are there foreign objects, contamination, or malfunctions on 
the paper transport rollers? 


Remove the obstructions or 
replace the component. 


5 


Toner cartridge 

Is the problem solved by replacing the toner cartridge with a 
new one? 


Replace the toner cartridge. 



he? 



Troubleshooting 



Print Quality Problems - 15 



P-13 Damaged Prints 




Problem 

The printed page is wrinkled, creased, or torn. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Fuser Assembly • Fuser Pressure Roller • Toner Cartridge 

• Transfer Roller Assy • Registration Roller Assy • Feeder Unit 

• Cassette Pickup Roller • Paper Cassette 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 


3 


Paper feed 

Is the paper fed obliquely? 


Go to "Skewed Image" 
table. 


4 


Paper path 

Are there obstructions such as burrs or foreign objects, or 
contamination on the paper path? 


Remove the obstructions or 
replace the component. 


5 


Paper path rollers 

Are there foreign objects, contamination, or malfunctions on 
the paper transport rollers? 


Remove the obstructions or 
replace the component. 



he? 



Troubleshooting 



Print Quality Problems - 16 



P-14 Unfused Image 




Problem 

The printed image is not fully fused to the paper. The image easily rub off. 
Initial Analysis 

Inspect the following components. Are they compatible with your printer ver- 
sion, correctly installed, not damaged, deformed or contaminated, or free of 
foreign objects sticking? 

• Fuser Assembly • Fuser Pressure Roller • DC Controller Board 

• Power Supply Assy 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Paper conditions (moisture, warp, etc.) 

Is the problem solved if you use new sheets of paper? 


Replace the paper. Advise 
the customer to stock paper 
in a dry place. 


2 


Fuser heater roller and fuser pressure roller 

Are there scratches, contamination, or foreign objects on the 
fuser heater roller or the fuser pressure roller? 


Replace the roller. 


3 


Fuser assembly 

Is there a proper pressure between the fuser heater roller 
and the fuser pressure roller? 


Replace the fuser assembly. 


4 


Paper path 

Are there obstructions such as burrs or foreign objects, or 
contamination on the paper path? 


Remove the obstructions or 
replace the component. 



he? 



Troubleshooting 



Print Quality Problems - 17 



P-15NoPhotoGrade 




Problem 

The printed image is not printing in PhotoGrade. 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


RAM Upgrade 

12 MB of RAM is required to turn on PhotoGrade (20 MB if 
using the duplex feature). 

Have you installed the necessary RAM? 


Install the RAM. 



-& 



Troubleshooting 



Print Quality Problems - 18 



P-16 No Duplex Printing 




Problem 

You cannot use the duplex printing option. 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Driver 

Are you using the driver version that came with the printer 
(or later)? 


Install the driver. 


2 


RAM Upgrade 

12 MB of RAM is required to use the duplex printing option 
(20 MB to turn on PhotoGrade). 24 MB is required to do 
duplex printing with PhotoGrade on legal-size paper. 

Have you installed the necessary RAM? 


Install the RAM. 



he? 



Troubleshooting 



Print Quality Problems - 19 



P-17 Duplex Page Upside-Down 

Problem 

The back side of a duplex page is printing upside-down. 



1 



Step 


Actions and Questions 


Action 
(When There Is Problem) 


1 


Driver 

Are you choosing the correct binding orientation in the 
driver? 


Make the correct selections. 



he? 



Troubleshooting 



Print Quality Problems - 20 



P-18 No Multipurpose Tray Printing 




Problem 

Paper feed problems from the multipurpose tray. 
Other visual/ audible symptoms: 

• Click from the manual feed solenoid 

• No rotation of the manual feed roller 

• Pressure plate not rising to create friction against manual feed roller 







Action 


Step 


Actions and Questions 


(When There Is Problem) 


1 


Did you recently take apart and possibly separate the Manual 


There are two gears on the 




Feed Clutch Gear? 


end of the Manual Feed 
Clutch Gear. Do not sepa- 
rate the two gears. Sepa- 
rating the gears may cause 
a small spring inside the 
gear to fall off, causing the 






Hyfeo) 


pickup roller not to 






rotate, resulting in a 








timeout paper jam. You 








cannot see this spring 








unless you separate the 




Manual Feed 


two gears on the clutch. 




Clutch Gear 


Make certain the small 
spring inside the Manual 
Feed Clutch Gear has not 
fallen off the black arm. 


2 


Did you recently complete the REA process? 


See action above. 



Service Source 




Upgrades 



LaserWriter 12/640 PS 



<m* 



l-^j Upgrades RAM Upgrade - 1 

RAM Upgrade 

The LaserWriter 12/640 PS comes with 4 MB of RAM, an amount that you can increase up 
to 64 MB. In addition to font caching and other calculation-oriented factors, increasing RAM 
is required to enable duplex printing and the PhotoGrade features. 

If you want to You need at least 

Use the duplex printing option 12 MB memory 

Turn on PhotoGrade 12 MB memory 

Use the duplex printing option and 20 MB memory 

turn on PhotoGrade (24 MB on legal size paper) 

The I/O board has two SIMM slots, marked C/D (on the left) and A/B (on the right). The 
table below lists RAM configurations you can use. 



^IIH^ 



m 



Upgrades 



RAM Upgrade - 2 



Slot c/ D 



Slot A/ B 




I/O Controller Board 



Total 


Slot C/ D 


Slot A/B 


4 MB 


MB 


4 MB 


8 MB 


4 MB 


4 MB 


8 MB 


MB 


8 MB 


12 MB 


4 MB 


8 MB 


12 MB 


8 MB 


4 MB 


16 MB 


8 MB 


8 MB 


16 MB 


MB 


16 MB 


20 MB 


4 MB 


16 MB 


24 MB 


8 MB 


16 MB 


32 MB 


16 MB 


16 MB 


32 MB 


MB 


32 MB 


36 MB 


4 MB 


32 MB 


40 MB 


8 MB 


32 MB 


48 MB 


16 MB 


32 MB 


48 MB 


32 MB 


16 MB 


64 MB 


32 MB 


32 MB 



K Service Source 




Take Apart 



LaserWriter 12/640 PS 



<m* 



m 



Take Apart 



Left Cover 



Left Cover 




Hook 1 



Left Cover 

Before you begin, pull out 
the cassette and open the top 
cover . 

1 Remove the two screws 
which fasten the rear 
end of the left cover. 

2 Shift the cover leftward 
to disengage the hidden 
hook at the lower right, 
raise the cover to clear 
the hidden hook on the 
top, and pull the cover 
from the printer. 



<m* 



m 



Take Apart 



Multipurpose Cover - 2 




Multipurpose 
Cover 



Multipurpose 
Cover 

Before you begin, pull out 
the cassette. 

1 Open the multipurpose 
cover . 

2 Disengage the pins at 
both sides in the lower 
part of the cover and 
open the cover further to 
about 90 degrees. 

3 Disengage the cover from 
the two claws and pull 
the cover off the printer. 



m 



Take Apart 



Multipurpose Tray - 3 




Multipurpose 
Tray 



Multipurpose Tray 

Before you begin, remove 
the multipurpose cover. 

1 Using a small flat -blade 
screwdriver, release the 
pin on the right side of 
the multipurpose tray 
and pull the tray from 
the printer. 



<m* 



gl 



Take Apart 



Top Cover 



Release- 
Lever 



Tab 1 



Top Cover 




Top Cover 

No preliminary steps are 
required before you begin 
this procedure. 

Note : Peform this 
procedure only if you must 
replace the top cover. 

1 Pull up the cover release 
and raise the top cover to 
about 90 degrees. 

2 Using a small flat -blade 
screwdriver, release the 
two tabs and lift the 
cover trim from the 
printer. (The cover 



Tab 2 



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m 



Take Apart 



Top Cover - 5 




trim is the 13 x 3.75 
inch plastic piece above 
the delivery rollers . ) 

Release the tab that 
retains the right hinge 
pin and slide the pin out 
of the printer. Repeat 
for the left hinge pin. 

Note : The two door- 
open springs referenced 
below are identical and 
interchangeable 

Remove the two door- 
open springs and lift the 
top cover from the 
printer . 



<m* 



gl 



Take Apart 



Main Cover 




Main Cover 



Main Cover 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

Note : The main cover is a 
fixed, one-piece housing 
that consists of the front, 
rear, and right panels. 
Seven screws secure the 
cover to the chassis. 

1 Remove the three screws 
on the front side, two 
screws on the top side, 
and the two screws on 



^IIH^ 



m 



Take Apart Main Cover - 7 

the rear side that secure the main cover to the chassis. 

2 Flex outward the edge of the cover just below the power 
switch and lift the cover straight up from the chassis. 

Replacement Note : A slight sideways pull from the I/O 
side helps seat the cover assembly. 



<m* 



m 



Take Apart 



I/O Board - 8 




I/O Board 



I/O Board 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

Note : Perform this 
procedure only if you are 
replacing a defective I/O 
board. If you are removing 
the board to get to a deeper 
part, perform the "I/O 
Shield" procedure. 

1 Remove the six screws 
and remove the I/O board 



^IIH^ 



m 



Take Apart 



I/O Board - 9 



I/O Bracket 




(with bracket) from the 
printer . 

Note : The I/O board 
connects to the engine 
through a receptacle 
connector. Remove the 
I/O board carefully to 
avoid damaging this 
connector 

2 Remove the two screws 
near the corner of the 
board and the four 
screws securing the 
connectors to the bracket 
and separate the bracket 
from the board. 



<m* 



m 



Take Apart 



I/O Shield - 1 




I/O Shield 



Connector 



I/O Shield 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the six screws 
that attach the I/O shield 
to the chassis and pull 
the I/O shield (with 
board in place) from the 
printer . 

Note : The I/O board 
connects to the engine 
through a receptacle 



^IIH^ 



m 



Take Apart I/O Shield -11 

connector. Remove the I/O shield carefully to avoid 
damaging this connector 



<m* 



gl 



Take Apart 



DC Controller Board - 1 2 




DC Control! 
Board 



DC Controller 
Board 

Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

I/O shield 

1 Remove the screw and 
the black cover plate. 

2 Remove the screw that 
secures the rear edge of 
the controller mount to 
the chassis. This screw 



Cover Plate 



^IIH^ 



m 



Take Apart DC Controller Board - 1 3 

is accessible through a rounded notch in the fuser 
assembly. 

3 Pull the DC controller board straight out of the printer. 
The board mates into a receptacle connector and may 
offer some resistance when you begin to pull. 

4 Disconnect all connectors on the board. 

Perform the step below only if you are replacing a defective 
board. 

5 Remove the two screws which fasten the DC controller 
board to its mount and separate the board from the 
mount . 



<m* 



gl 



Take Apart 



Laser/Scanner Assembly - 14 



J262 



Laser/Scanner 
Assembly 




Laser/Scanner 
Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the four screws 
at the base of the laser/ 
scanner assembly. 

2 Remove the one screw 
situated inside the round 
recess in top of the 
laser/scanner assembly. 



^IIH^ 



m 



Take Apart Laser/Scanner Assembly - 15 

Caution: Do not remove any of the three screws inside 
the square recesses. 

3 Lift the laser/scanner assembly, disconnect the two 

connectors, and remove the assembly from the printer. 



<m* 



gl 



Take Apart 



Registration Guide Assembly - 1 6 




Registration 
Guide Assembly 



Registration Guide 
Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Laser/scanner assembly 

1 Remove the five screws 
and remove the assembly 
from the printer. 

2 Remove the two screws 
and separate the angle 
from the rest of the 



^IIH^ 



m 



Take Apart Registration Guide Assembly - 1 7 

registration guide assembly. 



<m* 



gl 



Take Apart 



Fan Duct - 1 ; 




Fan Duct 



Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the screw, 
release the tab, and 
remove the duct from the 
printer . 



^IIH^ 



m 



Take Apart 



Fan -19 




Note: Connector J221 is empty 



Fan 



Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Fan duct 

1 Disconnect the fan cable 
from connector J222 on 
the power supply. 

2 Remove the long two 
screws and pull the fan 
from the chassis . 



J222 



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gl 



Take Apart 



Power Supply Assembly -20 



Note: Conne 




Power Supply 
Assembly 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Fan duct 

DC controller board. 

Place the printer on its 
side so that the fan 
point s upward . 

Disconnect the fan cable 
from the edge of the 



Power Supply Assembly 



^IIH^ 



m 



Take Apart Power Supply Assembly - 2 1 

power supply . 

3 Disconnect the large white connector next to the power 
switch. 

4 Remove the seven screws and separate the power supply 
assembly from the chassis . 

Proceed with steps below only if you are replacing a faulty 
power supply board. 



^IIH^ 



m 



Take Apart 



Power Supply Assembly -22 



Power Supply 
Board 




Remove the six screws 
which secure the power 
supply board to the 
plate. (One of them 
secures the grounding 
wire . ) 

Remove the two screws 
which secure the power 
inlet to the plate. 

Slide the power switch 
out of its guide and lift 
the power supply board 
from the plate. 



<m* 



gl 



Take Apart 



Cartridge Press Actuator -23 



Spring 




Cartridge Press 
Actuator 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the E-ring from 
the end of the geared 
cam. 

2 Working from the inside 
of the chassis, slide the 
cam from the guide plate. 

3 Remove the spring and 



^IIH^ 



m 



Take Apart Cartridge Press Actuator -24 

slide the guide plate down and outward to remove it from 
the printer. 



<m* 



gl 



Take Apart 



Cover Interlock Actuator -25 




Actuator 
Assembly 



Cover Interlock 
Actuator 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the five screws 
which secure the actu- 
ator assembly to the 
chassis . 

2 Detach the cam actuator 
from the interlock 
switch, release the tab, 



^IIH^ 



m 



Take Apart Cover Interlock Actuator -26 

and remove the cover interlock actuator. 



<m* 



m 



Take Apart 



Link Interlock Switch -27 




Link Interlock Switch 



Link Interlock 
Switch 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Cover interlock actuator 

• Power supply assembly 

1 Release the latch and pul 
out the link interlock 
switch. 



<m* 



m 



Take Apart 



Mirror Assembly - 2 I 



J301 



Guide 



Assembly 




Mirror Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Free the cable from the 
guide and disconnect the 
connector on the under- 
side of the assembly. 

2 Remove the two screws 
and lift the mirror 
assembly from the 
printer . 



<m* 



gl 



Take Apart 



Drive Transfer Assembly -29 



Drive Transfer 
A 




Drive Transfer 
Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Free the cable that runs 
across the plate. 

2 Remove the three screws 
and pull off the drive 
transfer assembly. 



^IIH^ 



m 



Take Apart 



Main Drive Assembly - 30 




sembl 



Main Drive 
Assembly 



Before you begin, remove 

the following: 
Left cover 
Multipurpose cover 
Multipurpose tray 
Main cover 
DC controller board 
Drive transfer assembly 

Remove the four screws 
and pull the main drive 
assembly from the 
chassis . 



<m* 



gl 



Take Apart 



Transfer Roller Assembly - 3 1 



Transfer Roller 
Assembf y 




Transfer Roller 
Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Using a small flatblade 
screwdriver, pry each 
end of the transfer 
roller shaft and remove 
the assembly from the 
printer . 

Replacement Note : Make 



m 



Take Apart Transfer Roller Assembly -32 

sure to fully seat the three tabs in the metal guide into the 
chassis . 



<m* 



m 



Take Apart 



Registration Roller Assembly - 3 3 



Registration Roller 
Assembly 




Registration Roller 
Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the two screws 
and lift out the registra- 
tion roller assembly. 



<m* 



m 



Take Apart 



Paper Deflector Solenoid - 3 4 




Paper Deflectt 
Solenoic 



Paper Deflector 
Solenoid 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Power suppy 

DC controller board 

Remove the two screws 
and slide the solenoid out 
of the chassis. 



<m* 



gl 



Take Apart 



Delivery Sensor - 3 5 




Mounting Plate 



Delivery Sensor Cable 



Delivery Sensor 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the three screws 
which secure the 
mounting plate to the 
chassis . 

2 As necessary, disconnect 
the cable, release the 
tabs, and remove the 
photo-interrupter from 
the chassis. 



^IIH^ 



m 



Take Apart Delivery Sensor - 3 6 

3 As necessary, remove the actuator (s) and springs (s) 
from the mounting plate. 



<m* 



m 



Take Apart 



Paper Deflector Guide - 3 7 



Paper Deflector Solenoid 




Bushing 



ushing 



tor 



Guide 



Paper Deflector 
Guide 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 At each end, release the 
white nylon bushing tabs 
that extend back into the 
chassis . 

2 Pull the paper deflector 
guide from the printer. 



<m* 



m 



Take Apart 



Cassette Feed Roller Bearing - 3 I 




Feed Rollei 
Bearing 



Cassette Feed 
Roller Bearing 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

1 Release the tab, shift the 
bearing rightward, and 
remove it from the 
chassis . 



<m* 



m 



Take Apart 



Cassette Feed Roller - 3 9 




Cassette Feed 
Roller 



Cassette Feed 
Roller 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Cassette feed roller 
bearing 

1 Release the tab and slide 
the cassette feed roller 
off the shaft. 



<m* 



gl 



Take Apart 



Pickup Motor and Solenoid - 4 



Cover Plate 



Pickup Motor 




Cassette Pickup Solenoid 



Pickup Motor and 
Solenoid 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the two screws 
and remove the pickup 
motor from the printer. 

2 Remove the four screws, 
press the claws of one of 
the support posts of the 
pickup drive assembly, 



^IIH^ 



m 



Take Apart Pickup Motor and Solenoid - 4 1 

and lift off the cover plate. 

3 Remove the one gear which conceals the pickup solenoid, 
remove the one screw, and remove the pickup solenoid 
from the printer. 



<m* 



gl 



Take Apart 



Registration Chute Assembly -42 




Chute 
Registrator 
Assembly 



Registration Chute 
Assembly 



Before you begin, remove 

the following: 
Left cover 
Multipurpose cover 
Multipurpose tray 
Main cover 
DC controller board 
Drive transfer assembly 
Cover interlock actuator 
Link interlock switch 
Pickup drive assembly 
Main drive assembly 

Remove the five screws 
which fasten the regis- 



^IIH^ 



m 



Take Apart Registration Chute Assembly -43 

tration chute assembly. 

2 Pull out the right side portion first and then take out the 
entire registration chute assembly, taking care not to 
bump the assembly against the chassis. 



<m* 



m 



Take Apart 



Cassette Pickup Roller -44 




Cassette Pickup Roller 



Cassette Pickup 
Roller 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Fan duct 

DC controller board 

Power supply assembly 

1 Release the claw and 

slide the cassette pickup 
roller from the shaft. 



<m* 



gl 



Take Apart 



Multipurpose Frame Assembly - 4 5 



P/J236-2 



P/J2 




P/J2342 



Multipurpose 
Frame Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Disconnect the two 

cables that run along the 
motor-side of the laser/ 
scanner assembly. 



^IIH^ 



m 



Take Apart 



Multipurpose Frame Assembly - 4 




Multipurpose 
Frame Assembly 



2 Remove the four screws 
and pull the multipur- 
pose frame assembly 
from the chassis . 



<m* 



m 



Take Apart 



Manual Feed Solenoid -47 



Multipurpose Frame Assem 




Manual Feed Solenoid 



Manual Feed 
Solenoid 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

1 Remove the one screw 
and pull the manual feed 
solenoid off the multi- 
purpose frame 
assembly. 



<m* 



m 



Take Apart 



Manual Feed Pickup Roller - 4 8 



Manual Feed 
Pickup Roller 



Mult 




Manual Feed 
Pickup Roller 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

1 Release the latch and 
slide the manual feed 
pickup roller off the 
multipurpose frame 
assembly. 



Assembly 



<m* 



m 



Take Apart 



Manual Feed Pickup Roller Holder -49 



Manual Feed Pickup 
Roller Holder 




Multipurpose Frame 
Assembly 



Manual Feed 
Pickup Roller 
Holder 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Manual feed pickup roller 

1 Remove the one screw, 
press the lever, and 
slide off the manual feed 
pickup roller. 



<m* 



gl 



Take Apart 



Manual Feed Clutch Gear - 5 



Manual Feed 
Clutch Gear 




Lever 
Gear 



Manual Feed 
Clutch Gear 



Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Manual feed pickup roller 

• Manual feed pickup roller 
holder 

1 Release the latch and 
slide the cam off the 

shaft. 



^IIH^ 



m 



Take Apart 



Manual Feed Clutch Gear - 5 1 




Lever 
Gear 



Manual Feed 
Clutch Gear 



2 Press the lever gear and 
pull the manual feed 
clutch gear from the 
multipurpose frame 
assembly. 

Note: Do not separate the 
two gears on the Manual Feed 
Clutch Gear (922-1964) . 
Separating the gears may 
cause the small spring 
inside the gear to fall off, 
causing the pickup roller 
not to rotate, resulting in a 
timeout paper jam. You 
cannot see this spring unless 
you separate the two gears 
on the clutch. 



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gl 



Take Apart 



Manual Feed Clutch Gear -52 




Multipurpose Frame 
Assembly 



Pressure Plate 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Manual feed pickup roller 

• Manual feed pickup roller 
holder 

• Manual feed clutch gear 

3 Release the pin on the 
left side and remove 
pressure plate from the 
multipurpose frame 
assembly. 



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m 



Take Apart Manual Feed Clutch Gear - 5 3 

Replacement Note : Place the spring over the positioning 
pin and hook the top of the spring in the small metal tab in 
the pressure plate. 



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gl 



Take Apart 



Manual Feed Paper-Present Sensor - 5 4 



Manual Feed Paper- 
Present Sensor 



Multipurpose Frame 
Assembly 




Manual Feed 

Paper-Present 

Sensor 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Manual feed pickup roller 

• Manual feed pickup roller 
holder 

• Manual feed clutch gear 

• Pressure plate 



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m 



Take Apart Manual Feed Paper-Present Sensor - 5 5 

1 Press the claw and remove the sensor. 



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gl 



Take Apart 



Separation Pad - 5 6 




Separation Pad 



Separation Pad 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Manual feed pickup roller 

• Manual feed pickup roller 
holder 

• Manual feed clutch gear 

• Pressure plate 

1 Press the claw from the 
bottom side to release 
the separation pad, turn 



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m 



Take Apart Separation Pad - 5 7 

the assembly about 90 degrees, slide it to align with the 
cuts in the support shaft, and remove it. 



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gl 



Take Apart 



Delivery Roller Shaft - 5 ! 




shing 



Delivery Roller 
Shaft 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Release the tab and slide 
the gear and bushing off 
the one end of the roller 
shaft. 

2 Release the tab at the 
opposite bushing and 
slide the delivery roller 



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m 



Take Apart Delivery Roller Shaft - 5 9 

shaft to clear the holes and remove the shaft from the 
printer . 



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m. 



Take Apart 



Fuser Assembly - 6 



J292 



Assembly 




Fuser Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Delivery roller shaft 

1 Disconnect the large 
white connector next to 
the power switch. 

2 Remove the four screws 
that secure the fuser 
assembly to the printer. 



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m 



Take Apart 



Fuser Assembly -61 



A 



Tape Upper 
Actuators Closed 




3 Raise the gear-side of the fuser and remove the entire 
assembly. 

Replacement Warning : The two exit actuators above the 
area of the fuser are extremely susceptible to damage during 
fuser replacement. Please tape these actuators closed as 
shown before reinstalling the fuser. Remove the tape after 
the fuser is in place. 



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gl 



Take Apart 



Fuser Pressure Roller -62 



Fuser Pressure Roller 




Fuser Pressure 
Roller 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

DC controller board 

Delivery roller shaft 

Fuser assembly 

Snap the roller shaft 
from its bearings and 
lift the pressure roller 
directly out of the 
chassis . 



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gl 



Take Apart 



Fuser Exit Sensor - 6 3 




Fuser Exit Senses 



Fuser Exit Sensor 

Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Fan duct 

DC controller board 

Power supply assembly 

1 Release the tabs and 

remove the sensor from 
the printer. 



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gl 



Take Apart 



Top Cover Latches -64 



Left Cover Latch 
Right Cover Latch 




Top Cover Latches 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Laser/scanner assembly 

1 Remove the screw that 
secures each latch and 
remove the latches from 
the printer. 



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gl 



Take Apart 



Cover Latch Shaft - 6 5 




Cover Latch Shaft 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Laser/scanner assembly 

• Top cover latches 

1 Pull the latch shaft 
rightward from the 
printer . 



^IIH^ 



gl 



Take Apart 



Pickup Drive Assembly - 6 6 




Pickup Drive 
Assembly 



Pickup Drive 
Assembly 



Before you begin, remove 

the following: 
Left cover 
Multipurpose cover 
Multipurpose tray 
Main cover 
DC controller board 
Power supply assembly 
Multipurpose frame assy 
Cassette feed roller 
bearing 

Put the printer on the 
rear side. 



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m 



Take Apart Pickup Drive Assembly -67 

2 Disconnect the harness of the pickup solenoid from the 
connector of the relay harness from the cassette size 
sensor assembly. 

3 Remove the four screws and remove the pickup drive 
assembly from the chassis . 



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Take Apart 



Preregistration Pinch Roller Assy - 6 I 



Jam Release PI 



Spring 



Stopper Rod 




Preregistration Pinch 
Roller Assembly 



Preregistration 
Pinch Roller Assy 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

• Pickup drive assembly 

• Chute registration assy 

1 Raise the jam release 
plate and remove the two 
springs and the stopper 
rod. 



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m 



Take Apart Preregistration Pinch Roller Assy -69 

2 Release the tabs and remove the pinch roller holder from 
the chassis. 

3 Remove the pinch roller assembly from the printer. 



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Take Apart 



Cassette Size Sensor - 7 



Cassette Size 
Sensor 




Cassette Size 

Sensor Assy 

922-1946 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

I/O shield 



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m 



Take Apart 



Cassette Size Sensor -71 




Cassette Size 

Sensor Assy 

922-1946 



1 Press in on the tab (on 
the back of the sensor 
assembly) that secures 
the assembly to the 
chassis . 

2 Push the assembly 
toward the front of the 
printer until the four 
other tabs are free. 

3 Disconnect the cables at 
J234 and J236 on the 
cassete size sensor 
board. 

4 Pull the assembly 
straight out of the 
printer . 



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Service Source 




Exploded View 



LaserWriter 12/640 PS 



«■► 



m 



Exploded View 



Overall Exploded View 



Left Cover 
922-1944 



Top Cover 
922-2185 




Cassette Paper- 
Present Actuator 
922-1960 
Cassette 
Pickup Roller 
922-1959 
Feed Bearing 
922-1957 

Cable, Cassette Size 

Sensor to Solenoids 

922-1947 

Cable, Cassette Size 

Sensor to Manual Feed 

922-1948 

Cassette Size 

Sensor Assy 

922-1946 



Universal 250 

Sheet Cassette 

922-1945 



Cable, 

Laser/Scanner 

922-1984 

Laser/Scanner 

Assembly 

661-1097 

Cover Latch Kit 
076-0589 

Transfer Roller Assy. 
922-1981 

Fuser Assembly 
661-1098 (110V) 
661-1099 (220V) 

Fuser Heater Roller 
922-1969 

Fuser Heater Bulb 
922-1970 (110V) 
922-1971 (220V) 

Fuser Pressure 
Roller Kit 
076-0537 

Cable, 

Start-of-Scan 

922-1985 

Solenoid, 

Deflector 
950 
Mirror 
Assembly 
922-1976 

Paper 
Deflector 
Guide 
922-1951 

Exit Roller Kit 

076-0701 



Cover Interlock 
Actuator Assy. 
922-1991 



Registration 
Chute Assembly 
922-1956 



Power Supply 

Assembly 

661-1100 (110V) 

661-1101 (220V) 



<<■► 



m 



Exploded View 



Left Cover 
922-1944 



Covers 



Top Cover 
922-2185 




Multipurpose Tray 
922-2183 



Multipurpose Cover 
922-2184 



<<■► 



m 



Exploded View 



Cassette 



Cable, Cassette Size Sensor to Solenoids 
922-1947 

Cable, Cassette Size Sensor to Manual Feed 
922-1948 




Universal 250 Sheet Cassette 
922-1945 



<<■► 



m 



Exploded View 



Paper Transportation 1 



Pickup Motor 
922-1955 



Registration Roller Assy. 
922-1949 

J X 




Cassette Feed Solenoid 
922-1954 

Cassette Paper- 
Present Actuator 
922-1960 



Cassette Pickup Roller 
922-1959 



Feed Bearing 
922-1957 



Registration Chute Assembly 
922-1956 



<<■► 



ffl 



Exploded View 



Paper Transportation 2 



Manual Feed Paper- 
Present Sensor 
922-1965 




Manual Feed 
Solenoid 
922-1962 



Preregistration Pinch 

Roller Assembly 

922-1961 



<<■► 



m 



Exploded View 



Fusing and Paper Exit 



Delivery Roller Shaft 
922-1974 




Fuser Assembly 
661-1098 (110V) 
661-1099 (220V) 



Fuser Exit Sensor 
922-1973 



<<■► 



m 



Exploded View 



Drive and Xerographic 



Laser/Scanner Assembly 
661-1097 



Drive Transfer Assembly 
922-1979 




Mirror Assembly 
922-1976 



<<■► 



m 



Exploded View 



Electrical 



Cable, Start-of-Scan 
922-1985 




<<■► 



m 



Exploded View 



Frame 



Static Eliminator 
922-1989 




Right Cassette Guide 
922-1992 



SMA308FE 



<<■► 



m 



Exploded View 



10 



500-Sheet Paper Feeder 



Size Sensor Board, Sheet Feeder 
922-1998 




SMA309FA 



500 Sheet Paper Cassette 
922-2000 



<<■► 



Service Source 




REA Program 



LaserWriter 12/640 PS 



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@j 



REA Program Introduction - 1 

Introduction 

A Repair Extension Authorization (REA) program has been 
initiated for the LaserWriter 12/640 PS printer. This 
program calls for the execution of four preventive mainte- 
nance procedures: 

• Removal of a capacitor from the DC controller board 

• Modification of an exit actuator 

• Inspection of the cassette pinch roller 

• Resetting of the multipurpose pressure plate. 

This document describes what printers are eligible, how to 
perform the procedures, and how to confirm printer opera- 
tion after completing the work. 



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REA Program 



Eligible Printers - 2 




Location of White Dot 




Location of Blue Dot 



Eligible Printers 



Before performing this repair, you must first confirm that 
the printer is eligible for the program by making the 
following observations. 

1 Pull the cassette from the printer and observe the face of 
the black chassis just to the left of where the cassette 
slides in. If there is a small white dot painted on the 
chassis, the repairs have already been performed. 

2 If there is not a white dot present, the printer is eligible 
for this program. 

Note: If the printer is still in its box, check for a blue dot on 
the UPC label on the outside of the box. The blue dot indicates 
that the REA work has already been done to the printer. 



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REA Program 



Take Apart - 3 



Take Apart 



Before you begin, remove the following: 
Left cover 
Multipurpose cover 
Multipurpose tray 
Main cover 
I/O shield 

DC controller board 
Delivery roller shaft 
Fuser assembly 
Multipurpose frame assembly 

Note: All the "first-remove" procedures above have been 
appended to the back of this document. To reassemble the 
printer, perform the procedures in reverse. 



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REA Program 



Capacitor Removal - 4 



Capacitor Removal 



Caution: While performing this procedure, use a grounded 
conductive workbench mat and grounding wriststrap, and 
ground your equipment to the mat. 



DC Controller Board 
(Component Side) 




An intermittent failure could lead to incorrect reporting of 
the printer's ready state. The removal of capacitor CI 02 on 
the DC controller board solves the problem. Following are 
two approved methods for removing the capacitor: removal 
by hand and removal by desoldering. 



^IIH^ 



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REA Program 



C102 



Capacitor Removal - 5 



Removal by Hand 

This is the preferred method of removing the capacitor and 
leads. 

1 Hold the board in one hand and grasp the capacitor in the 
other. Carefully rock the capacitor back and forth while 
holding the board by its edges. Continue to rock until the 
capacitor snaps loose. 




Rocking Motion 



^IIH^ 



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REA Program 



Capacitor Removal - 6 



Using an appropriate cutting tool, remove the two leads 
(if they have remained on the board after you removed 
the capacitor). Be careful not to damage any surrounding 
traces. Remove as much of the leads as possible to 
prevent potential shorting. 




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REA Program 



Capacitor Removal - 7 



Desolder Points 




DC Controller Board 
(Solder Side) 



Removal by Desoldering 

This is an alternate method of removing capacitor C102. 

1 Locate the two points on the solder-side of the board that 
correspond to capacitor C102. 

2 If you are using a vacuum-type soldering tool, apply 
heat to each of the points, suck the solder from the 
surface, and pull the capacitor from the board. 

3 If you are not using a vacuum-type soldering tool, apply 
enough heat to each of the points so that you can gently 
loosen the capacitor. Continue to rock the capacitor until 
you can easily remove it from the board. 

Note: If you are unable to remove the capacitor, you can 
order a replacement board that has no capacitor C102. The 
part number for the board is 661-1441. 



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REA Program 



Actuator Modification - 8 



A 



Actuator Modification 

Caution: The two upper exit actuators above the fuser are 
extremely susceptible to damage during fuser installation. 
Please tape them closed as shown before proceeding. Remove 
the tape after fuser replacement. 

In rare cases, removing paper jams from the fuser 
assembly can damage the lower exit actuator. This problem 
may be caused by tiny burrs at the tip of the actuator. This 
procedure removes any burrs that may exist. 



Tape Upper 
Actuators Closed 




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m 



REA Program 



Actuator Modification - 9 



Actuator Spring 



Exit Actuator 



Fuser Pressure Roller 




Locate the exit actuator 
near the left end of the 
fuser pressure roller. 

Pull the exit actuator, 
along with the actuator 
spring, out of the slot in 
the printer frame. 



^IIH^ 



m 



REA Program 



Actuator Modification - 10 



After Burnishing 




Gently rub a small piece 
of paper against the tip 
of the actuator about 
10-15 times. This 
burnishing action 
should remove any burrs 
that may exist. 



^IIH^ 



@j 



REA Program 



Actuator Modification - 11 



Actuator Spring 



Exit Actuator 




Reinstall the actuator 
spring onto the exit 
actuator. (See the illus- 
tration for correct posi- 
tioning of the spring.) 

Press the new exit actu- 
ator into the slot in the 
printer frame. 



^IIH^ 



m 



REA Program Actuator Modification - 12 

6 Use your finger to rock the exit actuator back and forth 
to make sure it moves freely and has a slight spring- 
action return. 

Important: The exit actuator must be correctly oriented 
and there must be sufficient tension in the spring. 
Otherwise, the actuator will not sense the absence of 
paper and a paper jam will be reported on power up. 

7 Wipe the pressure roller clean using a soft dry cotton 
cloth. 



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REA Program 



Pinch Roller Inspection - 13 



Pinch Roller 




Pinch Roller Inspection 



The pinch roller in the cassette provides a pressure surface 
against which the feed roller advances paper. If the pinch 
roller is misaligned, or its clearance from the feed roller 
too great, the feed roller may not grip properly and a paper 
jam can result. 







Pinch Roller 
Aligned 



Pinch Roller 
Misaligned 



Pinch Roller 
Clearance Too Great 



Note: Although this inspection is obviously critical if the 
customer is reporting pickup paper jams, these measures 



@j 



REA Program 



Pinch Roller Inspection - 14 



also serve to prevent the condition from developing in 
functioning units. 




wmm 

Checking Clearance 



Checking Alignment 

Remove the cassette and check the alignment of the roller. If 
the roller is not aligned fairly evenly across the pinch 
surface, make the adjustments described later in this topic. 
If the alignment is good, check for clearance. 

Checking Clearance 

When the cassette is installed, there should be a uniform 
clearance of approximately one millimeter between feed 
roller and pinch roller. 

In practical terms, this can be tested by holding the cassette 
in one hand and inserting a business card with the other hand 



@j 



REA Program 



Pinch Roller Inspection - 15 




Cover 



into the slit between the pinch roller and the plastic molded 
paper guide. With the cassette correctly oriented (top 
facing up), the card should just barely stay in place when 
you remove your hand. If the card falls through the opening 
in the cassette, the clearance is probably too great and 
should be adjusted. 

Making Adjustments 

1 Remove the two screws in the top face of the cassette and 
lift off the cover. 

2 Remove the one screw that attaches the roller bracket to 
the cassette. 

3 Inspect the mounting surface of the roller bracket. If it 
is not flat, carefully bend it until it is. 

4 Reinstall the roller and bracket, making sure the 
bracket seats securely in the two registration pins. 



Pinch Roller and Bracket 

wO tffl 

09 



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REA Program 



Pinch Roller Inspection - 16 



Replacement Note: There are four claws on the bottom of the 
cassette cover. Seat the claws in place and then secure the 
two screws on the top face. 



Claws 



Claws 




^IIH^ 



@j 



REA Program Pressure Plate Reset - 17 

Pressure Plate Reset 

The pressure plate is the surface in the multipurpose tray 
that presses paper up against the sweep of the pickup roller. 

To observe how the pressure plate works, hold the 
multipurpose frame assembly in your hand and deflect the 
plate with your thumb. A functional pressure plate should 
be free to pivot approximately half an inch (1.25 cm) up 
and down. A snagged pressure plate would not pivot up and 
down at all. 

This procedure resets the plate and its spring mechanism so 
that such a snag will not occur in the future. 



^IIH^ 



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REA Program 



Pressure Plate Reset - 18 



Before you begin, remove the following from the 
multipurpose frame assembly: 

• Manual feed pickup roller 

• Manual feed pickup roller holder 

• Manual feed clutch gear 



Clutch Gear 




Pickup Roller 



Roller Holder 



^IIH^ 



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REA Program 



Pressure Plate Reset - 19 



1 Carefully release the pivot pin at one end of the pressure 
plate and lift the plate from the multipurpose frame 
assembly. 




r Pressure 
Plate 



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REA Program 



Pressure Plate Reset - 20 



Reinstall the pressure plate, making sure the leaf spring 
on the underside of the plate rests on top of the plastic 
multi-feed preventer. Also make sure the compression 
spring is positioned correctly behind the separation pad. 



Leaf Spring 




Pressure 
Plate 



Compression 
Spring 



Separation Pad 



Multifeed Preventer 



^IIH^ 



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REA Program 



Pressure Plate Reset - 21 



After removing and reinstalling the pressure plate, test 
its movement. If it has the half-inch play referenced 
above, the plate will be functional. If not, repeat steps 1 
and 2. 




The tip of the leaf 
spring is visible when 
the pressure plate 
is correctly installed. 



^IIH^ 



m 



REA Program Confirming Printer Operation - 22 

Confirming Printer Operation 

After completing the two procedures and reassembling the 
printer, perform the following steps: 

1 Open the top cover and switch on power. After warming 
up, the jam light should illuminate. This indicates an 
operational DC controller board and top cover actuator 
system. 

2 Close the top cover. Send a print job to the printer (or 
wait for the startup page to print). If the page prints and 
exits into the delivery tray, the board and actuator 
system are confirmed operational. 

3 Connect a computer to the printer and print one page, 
using the multipurpose tray as the paper source. If the 
page picks up and feeds correctly, the multipurpose 
frame assembly is confirmed operational. 



@j 



REA Program 




Confirming Printer Operation - 23 



After confirming printer operation, you must mark the 
printer to show that it has undergone the REA work. The tool 
you will use is a DecoColor® opaque paint marker (white 
#300). This marker has been mailed to all service 
providers. 



Location of 
White Dot 



Note: Try the marker on a test surface before applying a 
mark to the printer. If you apply too much pressure, the 
paint may flow too quickly and run along the face of the 
chassis. Protect all adjacent surfaces. 

4 Using light pressure, press a white dot onto the face of 
the black chassis just to the left of where the cassette 
slides in. The dot should be approximately one eighth 
inch (2-10 mm) in diameter. 



^IIH^ 



m 



REA Program First-Remove Procedures - 24 

First-Remove Procedures 

The following topics are taken from the take apart chapter of 
the LaserWriter 12/640 PS manual. These are the steps 
that you must perform prior to commencing the 
LaserWriter 12/640 PS REA procedures described in the 
previous topics. 



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REA Program 



Left Cover - 25 



Left Cover 




Hookl 



Left Cover 



Before you begin, pull out 
the cassette and open the top 
cover. 

1 Remove the two screws 
which fasten the rear 
end of the left cover. 

2 Shift the cover leftward 
to disengage the hidden 
hook at the lower right, 
raise the cover to clear 
the hidden hook on the 
top, and pull the cover 
from the printer. 



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REA Program 



Multipurpose Cover - 26 




Multipurpose 
Cover 



Multipurpose 
Cover 

Before you begin, pull out 
the cassette. 

1 Open the multipurpose 
cover. 

2 Disengage the pins at 
both sides in the lower 
part of the cover and 
open the cover further to 
about 90 degrees. 

3 Disengage the cover from 
the two claws and pull 
the cover off the printer. 



m 



REA Program 



Multipurpose Tray - 27 




Multipurpose 
Tray 



Multipurpose Tray 

Before you begin, remove 
the multipurpose cover. 

1 Using a small flat-blade 
screwdriver, release the 
pin on the right side of 
the multipurpose tray 
and pull the tray from 
the printer. 



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REA Program 



Main Cover - 28 




Main Cover 



Main Cover 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

Note: The main cover is a 
fixed, one-piece housing 
that consists of the front, 
rear, and right panels. 
Seven screws secure the 
cover to the chassis. 

1 Remove the three screws 
on the front side, two 
screws on the top side, 
and the two screws on 



m 



REA Program Main Cover - 29 

the rear side that secure the main cover to the chassis. 

2 Flex outward the edge of the cover just below the power 
switch and lift the cover straight up from the chassis. 

Replacement Note: A slight sideways pull from the I/O side 
helps seat the cover assembly. 



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REA Program 



I/O Shield - 30 




Location of 
Receptacle 
Connector 



I/O Shield 



I/O Shield 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Remove the six screws 
that attach the I/O 
shield to the chassis and 
pull the I/O shield 
(with board in place) 
from the printer. 

Note: The I/O board 
connects to the engine 
through a receptacle 



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m 



REA Program I/O Shield - 31 

connector. Remove the I/O shield carefully to avoid 
damaging this connector 



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REA Program 



DC Controller Board - 32 




DC Controller 
Board 



DC Controller 
Board 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

I/O shield 

Remove the screw and 
the black cover plate. 

Remove the screw that 
secures the rear edge of 
the controller mount to 
the chassis. This screw 



Cover Plate 



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@j 



REA Program DC Controller Board - 33 

is accessible through a rounded notch in the fuser 
assembly. 

3 Pull the DC controller board straight out of the printer. 
The board mates into a receptacle connector and may 
offer some resistance when you begin to pull. 

4 Disconnect all connectors on the board. 

5 Remove the two screws which fasten the DC controller 
board to its mount and separate the board from the 
mount. 



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REA Program 



Delivery Roller Shaft - 34 




Bushing 



Delivery Roller 
Shaft 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Release the tab and slide 
the gear and bushing off 
the end of the shaft. 

2 Release the tab at the 
opposite bushing, slide 
the shaft to clear the 
holes, and remove the 
shaft from the printer. 



@j 



REA Program 



Fuser Assembly - 35 



J292 -^^ ; 



Fuser Assembly 




Fuser Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Delivery roller shaft 

1 Disconnect the large 
white connector next to 
the power switch. 

2 Remove the four screws 
that secure the fuser 
assembly to the printer. 



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REA Program 



A 



Tape Upper 
Actuators Closed 



Fuser Assembly - 36 



3 Raise the gear-side of the fuser and remove the entire 
assembly. 




Replacement Warning: The two exit actuators above the area 
of the fuser are extremely susceptible to damage during 
fuser replacement. Please tape these actuators closed as 
shown before reinstalling the fuser. Remove the tape after 
the fuser is in place. 



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REA Program 



Multipurpose Frame Assembly - 37 



P/J 236-2 



P/J2 




P/J 2342 



Multipurpose 
Frame Assembly 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

1 Disconnect the two 

cables that run along the 
motor-side of the laser/ 
scanner assembly. 



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@j 



REA Program 



Multipurpose Frame Assembly - 38 




Multipurpose 
Frame Assembly 



2 Remove the four screws 
and pull the multipur- 
pose frame assembly 
from the chassis. 



^IIH^ 



@j 



REA Program 



Manual Feed Pickup Roller - 39 



Manual Feed 
Pickup Roller 




Multipurpose Frame 
Assembly 



Manual Feed 
Pickup Roller 

Before you begin, remove 
the following: 

• Left cover 

• Multipurpose cover 

• Multipurpose tray 

• Main cover 

• Multipurpose frame assy 

1 Release the latch and 
slide the manual feed 
pickup roller off the 
multipurpose frame 
assembly. 



^IIH^ 



@j 



REA Program 



Manual Feed Pickup Roller Holder - 40 



Manual Feed Pickup 
Roller Holder 




Multipurpose Frame 
Assembly 



Manual Feed 
Pickup Roller 
Holder 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Multipurpose frame assy 

Manual feed pickup roller 

Remove the one screw, 
press the lever, and 
slide off the manual feed 
pickup roller. 



^IIH^ 



@j 



REA Program 



Manual Feed Clutch Gear - 41 



Manual Feed 
Clutch Gear 




Lever 
Gear 



Manual Feed 
Clutch Gear 



Before you begin, remove 
the following: 

Left cover 

Multipurpose cover 

Multipurpose tray 

Main cover 

Multipurpose frame assy 

Manual feed pickup roller 

Manual feed pickup 

roller holder 

1 Release the latch and 
slide the cam off the 
shaft. 



^IIH^ 



@j 



REA Program Manual Feed Clutch Gear - 42 

2 Press the lever gear and 
pull the manual feed 
clutch gear from the 
multipurpose frame 
assembly. 



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